Primary memory, also known as main memory, is used to store data and instructions that the CPU is currently processing. It has limited capacity and is volatile, meaning data is lost when power is turned off. RAM and ROM are types of primary memory. Secondary memory is used for permanent storage and includes hard disks, CDs, DVDs. It has larger capacity but is slower to access. Memory is organized in a hierarchy with registers being fastest, then RAM, and finally secondary storage being slowest but able to store the most data.
The document discusses various types of computer memory technologies, including RAM types like DRAM, SRAM, DDR, DDR2, and DDR3. It explains the memory hierarchy from registers to cache to main memory to disks. Key points covered include how DRAM works using capacitors that must be periodically refreshed, advantages of SDRAM over regular DRAM like pipelining commands. Generations of DDR memory are compared in terms of clock speeds, data rates, and other features.
RAM allows stored data to be accessed directly in any random order. There are two main types: static RAM and dynamic RAM. Static RAM keeps data without refreshing but is more expensive, while dynamic RAM needs refreshing but is cheaper. RAM is a temporary memory that does not store data permanently once power is turned off. Future RAM technologies aim to provide smaller, faster, and cheaper memory chips compared to today's options like DDR3 RAM.
This document discusses the memory hierarchy in computers. It begins by explaining that computer memory is organized in a pyramid structure from fastest and smallest memory (cache) to slower and larger auxiliary memory. The main types of memory discussed are RAM, ROM, cache memory, and auxiliary storage. RAM is further divided into SRAM and DRAM. The document provides details on the characteristics of each memory type including access speed, volatility, capacity and cost. Diagrams are included to illustrate concepts like RAM, ROM, cache levels and auxiliary devices. Virtual memory is also briefly introduced at the end.
Primary memory, also known as main memory, is the memory that is directly accessible by the CPU. It holds the data and instructions currently being processed. Primary memory is generally made up of semiconductor devices like RAM and ROM. RAM is volatile and loses its data when power is removed, while ROM retains its data permanently. There are different types of RAM such as SRAM, DRAM, SDRAM, and DDR that have evolved over time. ROM includes mask ROM, PROM, EPROM, EEPROM, and flash ROM, which have different characteristics regarding read/write capabilities and whether they need power to retain data.
Computer memory comes in several types and serves different functions. The main types are random access memory (RAM), read only memory (ROM), cache memory, and secondary memory. RAM is volatile and used for main memory, while ROM is non-volatile and stores permanent data. Cache memory temporarily stores data and instructions from main memory to speed up the processor. Secondary memory includes hard disks for long-term storage.
Cache is a small amount of fast memory located close to the CPU that stores frequently accessed instructions and data. It speeds up processing by allowing the CPU to access needed information more quickly than from main memory. Caches exploit the principle of locality of reference, where programs tend to access the same data/instructions repeatedly over short periods. There are multiple cache levels, with L1 cache being fastest but smallest and L3 cache being largest but slower. Caching improves performance dramatically by fulfilling over 90% of memory requests from the small cache rather than requiring slower access to main memory.
Registers are small data holding places within a computer's processor. They typically hold instructions, addresses, or data and perform fetch, decode, and execute functions. The main types of registers include memory address registers, memory data registers, index registers, general purpose registers, program counters, pointer registers, accumulator registers, stack control registers, and flag registers. Flag registers in particular contain status flags that indicate conditions like carry, zero, or overflow from executed instructions.
The document discusses various types of computer memory technologies, including RAM types like DRAM, SRAM, DDR, DDR2, and DDR3. It explains the memory hierarchy from registers to cache to main memory to disks. Key points covered include how DRAM works using capacitors that must be periodically refreshed, advantages of SDRAM over regular DRAM like pipelining commands. Generations of DDR memory are compared in terms of clock speeds, data rates, and other features.
RAM allows stored data to be accessed directly in any random order. There are two main types: static RAM and dynamic RAM. Static RAM keeps data without refreshing but is more expensive, while dynamic RAM needs refreshing but is cheaper. RAM is a temporary memory that does not store data permanently once power is turned off. Future RAM technologies aim to provide smaller, faster, and cheaper memory chips compared to today's options like DDR3 RAM.
This document discusses the memory hierarchy in computers. It begins by explaining that computer memory is organized in a pyramid structure from fastest and smallest memory (cache) to slower and larger auxiliary memory. The main types of memory discussed are RAM, ROM, cache memory, and auxiliary storage. RAM is further divided into SRAM and DRAM. The document provides details on the characteristics of each memory type including access speed, volatility, capacity and cost. Diagrams are included to illustrate concepts like RAM, ROM, cache levels and auxiliary devices. Virtual memory is also briefly introduced at the end.
Primary memory, also known as main memory, is the memory that is directly accessible by the CPU. It holds the data and instructions currently being processed. Primary memory is generally made up of semiconductor devices like RAM and ROM. RAM is volatile and loses its data when power is removed, while ROM retains its data permanently. There are different types of RAM such as SRAM, DRAM, SDRAM, and DDR that have evolved over time. ROM includes mask ROM, PROM, EPROM, EEPROM, and flash ROM, which have different characteristics regarding read/write capabilities and whether they need power to retain data.
Computer memory comes in several types and serves different functions. The main types are random access memory (RAM), read only memory (ROM), cache memory, and secondary memory. RAM is volatile and used for main memory, while ROM is non-volatile and stores permanent data. Cache memory temporarily stores data and instructions from main memory to speed up the processor. Secondary memory includes hard disks for long-term storage.
Cache is a small amount of fast memory located close to the CPU that stores frequently accessed instructions and data. It speeds up processing by allowing the CPU to access needed information more quickly than from main memory. Caches exploit the principle of locality of reference, where programs tend to access the same data/instructions repeatedly over short periods. There are multiple cache levels, with L1 cache being fastest but smallest and L3 cache being largest but slower. Caching improves performance dramatically by fulfilling over 90% of memory requests from the small cache rather than requiring slower access to main memory.
Registers are small data holding places within a computer's processor. They typically hold instructions, addresses, or data and perform fetch, decode, and execute functions. The main types of registers include memory address registers, memory data registers, index registers, general purpose registers, program counters, pointer registers, accumulator registers, stack control registers, and flag registers. Flag registers in particular contain status flags that indicate conditions like carry, zero, or overflow from executed instructions.
RAM(Random Access Memory) is a part of computer's Main Memory which is directly accessible by CPU. RAM is used to Read and Write data into it which is accessed by CPU randomly. RAM is volatile in nature, it means if the power goes off, the stored information is lost.
Main memory is the internal storage area in a computer that temporarily stores data and programs. It includes RAM and ROM and allows for quick access of data by the CPU. Secondary memory provides long-term storage of data and programs not currently in use, such as on hard disks, CDs, DVDs, and USB drives. Computer memory is measured in bits, bytes, kilobytes, megabytes, gigabytes, and terabytes, with each unit being a multiple of the previous unit by a factor of 1024.
Working principle of a hard disk controllerMarajulislam3
A hard disk controller (HDC) is an electrical component within a computer hard disk that enables the processor or CPU to access, read, write, delete and modify data to and from the hard disk. Essentially, an HDC allows the computer or its processor to control the hard disk.
This document discusses various types of external storage devices, including hard disk drives, solid state drives, flash memory, optical discs, and future technologies. It provides details on how hard disk drives use spinning disks and magnetic heads to read and write data. Solid state drives have no moving parts and use integrated circuits for memory. USB flash drives are small, removable flash memory devices. Optical discs like CDs and DVDs store data in spiral tracks of tiny bumps burned by a laser onto the disc's surface. Future storage technologies may use helium instead of air in hard drives for higher capacity and kinetic drives that interface over ethernet.
Introduction to Bus | Address, Data, Control BusHem Pokhrel
Handouts for BBa First Semester Prime College.
UNIT 5: Central Processing Unit: Control Unit, Arithmetic and Logic Unit, Register set, Functions of Central Processing Unit. Introduction to Bus (Address, Data, Control)
This document provides information about RAM and ROM, two types of computer memory. RAM (Random Access Memory) is volatile memory that allows reading and writing and is used to run applications, while ROM (Read Only Memory) is non-volatile and only allows reading to store programs for booting the computer. Key differences between RAM and ROM are outlined, such as RAM being faster but losing data when powered off, while ROM retains data when powered off but only allows writing once. Characteristics of each type of memory are also described.
The control unit is responsible for controlling the flow of data and operations in a computer. It generates timing and control signals to coordinate the arithmetic logic unit, memory, and other components. Control units can be implemented using either hardwired or microprogrammed logic. A hardwired control unit uses combinational logic circuits like gates and flip-flops to directly generate control signals, while a microprogrammed control unit stores control sequences as microprograms in a control memory and executes them step-by-step using microinstructions. Both approaches have advantages and disadvantages related to speed, flexibility, cost, and complexity of implementation.
RAM, or Random Access Memory, is a type of data storage used in computers that is located on the motherboard and allows quick access by the processor. There are two main types of RAM: DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). DRAM needs to be refreshed often and uses a single transistor and capacitor per bit, while SRAM does not need to be refreshed and uses an array of six transistors per bit, making it faster to access but more expensive than DRAM.
Cache memory is a small amount of fast SRAM located between the CPU and main memory that stores frequently accessed data. When the CPU requests data, the cache memory is checked first and if the data is present it can be accessed much faster than main memory. If the data is not in cache memory, it is retrieved from main memory which is slower but larger DRAM. Modern processors use a multi-level cache system with multiple cache levels (L1, L2, etc.) checked sequentially to improve performance.
The document discusses the history and components of the central processing unit (CPU). It describes how the CPU originated from concepts developed in the 1940s and evolved from large mainframe computers to smaller microprocessors. The key components of the CPU are the control unit, arithmetic logic unit, and memory unit. The CPU functions by fetching instructions from memory, decoding and translating them, executing calculations and data movement, and storing results.
The document discusses the main components of a computer motherboard. It describes the CPU socket, memory slots, CMOS battery, expansion slots like ISA, PCI, and AGP, power connectors, chipset including the northbridge and southbridge, graphical devices, and back panel ports. The motherboard holds many crucial electronic components like the CPU and memory and provides connections for other peripherals.
This document provides an overview of random access memory (RAM). It discusses that RAM is a type of volatile memory used to store running programs and data. The document outlines the history, technologies, components, types (SRAM and DRAM), capacities, manufacturers, and advantages/disadvantages of RAM. It also includes diagrams of a RAM block and the positioning and structure of RAM modules.
The document provides an overview of different types of computer memory and storage. It discusses the two main types of memory - primary/main memory which is volatile and includes RAM and ROM, and secondary memory which is non-volatile such as hard disks, flash drives, and optical discs. RAM is further divided into static and dynamic RAM. ROM includes PROM, EPROM, and EEPROM. The document then describes the history and workings of various secondary storage technologies like magnetic tapes, disks, optical discs like CDs and DVDs, and solid state flash memory.
The CPU carries out computer program instructions and performs basic operations. It contains a microprocessor with transistors and wires that control the computer's activities by interacting with other components on the motherboard. There are two types of memory: RAM is volatile and can lose data when powered off, while ROM is non-volatile and retains data when off. The motherboard is the main circuit board that holds crucial components like the CPU and memory, and provides connections for peripherals.
The document discusses the memory hierarchy in computers. It describes the different levels of memory from fastest to slowest as register memory, cache memory, main memory (RAM and ROM), and auxiliary memory (magnetic tapes, hard disks, etc.). The main memory directly communicates with the CPU while the auxiliary memory provides backup storage and needs to transfer data to main memory to be accessed by the CPU. A cache memory is also used to increase processing speed.
RAM is the primary memory of a computer that can access any memory cell directly. The two main types are DRAM and SRAM. DRAM (dynamic RAM) is commonly used in computers and needs to be refreshed to retain data. It stores each bit in a storage cell with a capacitor and transistor. ROM is a permanent, non-volatile memory that usually cannot be written to by the user. The main types are PROM, EPROM, EEPROM and flash memory.
This document provides information on different types of computer memory, including ROM and RAM. It discusses the main characteristics and uses of ROM types like PROM, EPROM, and EEPROM (including EAROM and flash memory). It also covers the basics of RAM like SDRAM, and specific types like SDR-SDRAM, DDR-SDRAM, and RDRAM. The document is intended to explain the differences between read-only and random access memory.
Primary Memory: RAM, ROM and their TypesHem Pokhrel
Random Access Memory and Read Only Memory along with their types:
Content includes basic introduction of SRAM, DRAM, NvRAM, Masked ROM, PROM, EPROM, EEPROM
This document discusses different types of computer memory. It begins by defining memory as the physical devices used to temporarily or permanently store programs and data for use in a computer. It then describes the main types of memory as main memory, which temporarily stores currently executing data and instructions (e.g. RAM), and secondary memory, which permanently stores data for later use (e.g. hard disks). The document goes on to provide details on different technologies used for RAM, ROM, cache memory, and storage devices.
This document discusses different types of computer memory and storage devices. It defines primary and secondary storage. Primary storage includes RAM and ROM, which temporarily and permanently store data respectively. RAM is volatile and includes DRAM, SRAM, and RDRAM. ROM is non-volatile and includes PROM, EPROM, EEPROM, and flash memory. The document provides details on each type of memory, including their characteristics and uses.
RAM(Random Access Memory) is a part of computer's Main Memory which is directly accessible by CPU. RAM is used to Read and Write data into it which is accessed by CPU randomly. RAM is volatile in nature, it means if the power goes off, the stored information is lost.
Main memory is the internal storage area in a computer that temporarily stores data and programs. It includes RAM and ROM and allows for quick access of data by the CPU. Secondary memory provides long-term storage of data and programs not currently in use, such as on hard disks, CDs, DVDs, and USB drives. Computer memory is measured in bits, bytes, kilobytes, megabytes, gigabytes, and terabytes, with each unit being a multiple of the previous unit by a factor of 1024.
Working principle of a hard disk controllerMarajulislam3
A hard disk controller (HDC) is an electrical component within a computer hard disk that enables the processor or CPU to access, read, write, delete and modify data to and from the hard disk. Essentially, an HDC allows the computer or its processor to control the hard disk.
This document discusses various types of external storage devices, including hard disk drives, solid state drives, flash memory, optical discs, and future technologies. It provides details on how hard disk drives use spinning disks and magnetic heads to read and write data. Solid state drives have no moving parts and use integrated circuits for memory. USB flash drives are small, removable flash memory devices. Optical discs like CDs and DVDs store data in spiral tracks of tiny bumps burned by a laser onto the disc's surface. Future storage technologies may use helium instead of air in hard drives for higher capacity and kinetic drives that interface over ethernet.
Introduction to Bus | Address, Data, Control BusHem Pokhrel
Handouts for BBa First Semester Prime College.
UNIT 5: Central Processing Unit: Control Unit, Arithmetic and Logic Unit, Register set, Functions of Central Processing Unit. Introduction to Bus (Address, Data, Control)
This document provides information about RAM and ROM, two types of computer memory. RAM (Random Access Memory) is volatile memory that allows reading and writing and is used to run applications, while ROM (Read Only Memory) is non-volatile and only allows reading to store programs for booting the computer. Key differences between RAM and ROM are outlined, such as RAM being faster but losing data when powered off, while ROM retains data when powered off but only allows writing once. Characteristics of each type of memory are also described.
The control unit is responsible for controlling the flow of data and operations in a computer. It generates timing and control signals to coordinate the arithmetic logic unit, memory, and other components. Control units can be implemented using either hardwired or microprogrammed logic. A hardwired control unit uses combinational logic circuits like gates and flip-flops to directly generate control signals, while a microprogrammed control unit stores control sequences as microprograms in a control memory and executes them step-by-step using microinstructions. Both approaches have advantages and disadvantages related to speed, flexibility, cost, and complexity of implementation.
RAM, or Random Access Memory, is a type of data storage used in computers that is located on the motherboard and allows quick access by the processor. There are two main types of RAM: DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). DRAM needs to be refreshed often and uses a single transistor and capacitor per bit, while SRAM does not need to be refreshed and uses an array of six transistors per bit, making it faster to access but more expensive than DRAM.
Cache memory is a small amount of fast SRAM located between the CPU and main memory that stores frequently accessed data. When the CPU requests data, the cache memory is checked first and if the data is present it can be accessed much faster than main memory. If the data is not in cache memory, it is retrieved from main memory which is slower but larger DRAM. Modern processors use a multi-level cache system with multiple cache levels (L1, L2, etc.) checked sequentially to improve performance.
The document discusses the history and components of the central processing unit (CPU). It describes how the CPU originated from concepts developed in the 1940s and evolved from large mainframe computers to smaller microprocessors. The key components of the CPU are the control unit, arithmetic logic unit, and memory unit. The CPU functions by fetching instructions from memory, decoding and translating them, executing calculations and data movement, and storing results.
The document discusses the main components of a computer motherboard. It describes the CPU socket, memory slots, CMOS battery, expansion slots like ISA, PCI, and AGP, power connectors, chipset including the northbridge and southbridge, graphical devices, and back panel ports. The motherboard holds many crucial electronic components like the CPU and memory and provides connections for other peripherals.
This document provides an overview of random access memory (RAM). It discusses that RAM is a type of volatile memory used to store running programs and data. The document outlines the history, technologies, components, types (SRAM and DRAM), capacities, manufacturers, and advantages/disadvantages of RAM. It also includes diagrams of a RAM block and the positioning and structure of RAM modules.
The document provides an overview of different types of computer memory and storage. It discusses the two main types of memory - primary/main memory which is volatile and includes RAM and ROM, and secondary memory which is non-volatile such as hard disks, flash drives, and optical discs. RAM is further divided into static and dynamic RAM. ROM includes PROM, EPROM, and EEPROM. The document then describes the history and workings of various secondary storage technologies like magnetic tapes, disks, optical discs like CDs and DVDs, and solid state flash memory.
The CPU carries out computer program instructions and performs basic operations. It contains a microprocessor with transistors and wires that control the computer's activities by interacting with other components on the motherboard. There are two types of memory: RAM is volatile and can lose data when powered off, while ROM is non-volatile and retains data when off. The motherboard is the main circuit board that holds crucial components like the CPU and memory, and provides connections for peripherals.
The document discusses the memory hierarchy in computers. It describes the different levels of memory from fastest to slowest as register memory, cache memory, main memory (RAM and ROM), and auxiliary memory (magnetic tapes, hard disks, etc.). The main memory directly communicates with the CPU while the auxiliary memory provides backup storage and needs to transfer data to main memory to be accessed by the CPU. A cache memory is also used to increase processing speed.
RAM is the primary memory of a computer that can access any memory cell directly. The two main types are DRAM and SRAM. DRAM (dynamic RAM) is commonly used in computers and needs to be refreshed to retain data. It stores each bit in a storage cell with a capacitor and transistor. ROM is a permanent, non-volatile memory that usually cannot be written to by the user. The main types are PROM, EPROM, EEPROM and flash memory.
This document provides information on different types of computer memory, including ROM and RAM. It discusses the main characteristics and uses of ROM types like PROM, EPROM, and EEPROM (including EAROM and flash memory). It also covers the basics of RAM like SDRAM, and specific types like SDR-SDRAM, DDR-SDRAM, and RDRAM. The document is intended to explain the differences between read-only and random access memory.
Primary Memory: RAM, ROM and their TypesHem Pokhrel
Random Access Memory and Read Only Memory along with their types:
Content includes basic introduction of SRAM, DRAM, NvRAM, Masked ROM, PROM, EPROM, EEPROM
This document discusses different types of computer memory. It begins by defining memory as the physical devices used to temporarily or permanently store programs and data for use in a computer. It then describes the main types of memory as main memory, which temporarily stores currently executing data and instructions (e.g. RAM), and secondary memory, which permanently stores data for later use (e.g. hard disks). The document goes on to provide details on different technologies used for RAM, ROM, cache memory, and storage devices.
This document discusses different types of computer memory and storage devices. It defines primary and secondary storage. Primary storage includes RAM and ROM, which temporarily and permanently store data respectively. RAM is volatile and includes DRAM, SRAM, and RDRAM. ROM is non-volatile and includes PROM, EPROM, EEPROM, and flash memory. The document provides details on each type of memory, including their characteristics and uses.
This document discusses computer memory systems including main memory, cache, and virtual memory. It defines main memory as the central storage location that holds programs and data currently being used by the CPU. The document outlines memory hierarchy from fastest to slowest as registers, cache, main memory, and secondary storage. It describes RAM and ROM types as well as cache memory. Locality of reference and memory technologies such as magnetic disks are also summarized.
cache memory and cloud computing technologyssuserf86fba
Memory can be either primary (internal/main memory) or secondary (external storage). Primary memory is volatile and holds data temporarily, while secondary memory is non-volatile for permanent storage. Primary memory includes RAM (random access memory) and ROM (read only memory). RAM is used to run programs and can be DRAM (dynamic RAM) or SRAM (static RAM). ROM includes PROM, EPROM, and EEPROM which cannot be written to like RAM. Caches like L1, L2, and L3 exist between the CPU and main memory for faster access to frequently used instructions and data.
its about computer storage and its managements how to manage the memory, in a...ssuserf86fba
Memory can be either primary (main) memory or secondary memory. Primary memory, like RAM, is directly accessible by the CPU and volatile, meaning it loses data when powered off. It includes RAM (random access memory) and ROM (read only memory). RAM is used for temporary storage and comes in DRAM and SRAM types, while ROM stores permanent, unalterable data like the BIOS. Secondary memory, like hard disks, is non-volatile and used for long-term storage. Caches like L1, L2, and L3 caches improve performance by storing frequently used data and instructions between the CPU and main memory.
Introduction, Memory Hierarchy, Random Access Memory (RAM), Types of RAM, Read Only Memory (ROM), Types of ROM. Introduction, Classification of Secondary Storage Devices, Magnetic Tape, Magnetic Disk, Optical Disk, Magneto Optical disk.
The document discusses computer memory organization and hierarchy. It begins by defining main memory and auxiliary memory. The memory hierarchy is described as a pyramid structure where the cost of memory increases and capacity decreases as speed increases, from registers to tertiary storage. Cache memory bridges the gap between the processor and main memory. RAM is volatile memory that can be written to and altered, while ROM is non-volatile memory that can only be read from. The bootstrap loader stored in ROM's memory is needed to start the computer software when power is turned on.
The document summarizes the major internal and external components of a typical computer system. It describes the system unit/case and motherboard as housing the central components. The motherboard connects the processor, memory, storage, ports and expansion slots. Key internal components are then explained in more detail, including the CPU, RAM, hard drive, optical drives, and power supply. External components such as ports, buttons and connectors are also outlined. The document provides a high-level overview of the basic parts that make up a computer system.
The document provides information about computer memory. It discusses different types of computer memory like registers, cache memory, RAM, ROM, and secondary storage devices. Registers provide the fastest access but have limited storage. Cache memory is faster than RAM and stores recently accessed data. RAM is used for temporary storage and ROM is used for permanent storage. Secondary storage devices like hard disks provide large storage but have slower access times than primary memory. The memory hierarchy ensures fast memory like registers are closest to the CPU while slower secondary storage is farther away.
Computer memory can be divided into three main types: cache memory, primary/main memory, and secondary memory. Primary memory is the working memory of the computer, usually made up of semiconductor devices like RAM and ROM. Secondary memory is for long-term storage, includes magnetic disks, optical disks like CDs/DVDs, and tapes. Memory is also divided into smaller units called cells that each have a unique address from 0 to the total memory size minus one.
Main memory is made up of RAM and ROM chips. RAM is read-write memory that can be accessed randomly; data is lost when power is off. There are static and dynamic RAM types. Static RAM retains data indefinitely if powered, dynamic RAM must be periodically refreshed. ROM is read-only and permanently stores data. There are mask, PROM, EPROM and EEPROM ROM types that can be programmed at different stages. Cache memory uses fast static RAM. Main memory often uses dynamic RAM for its ability to store large amounts of data at lower cost despite slower access.
The document summarizes the key internal and external components of a computer system. It describes the motherboard as the main circuit board that holds the CPU and connects all other components. The CPU processes instructions using RAM for temporary storage and ROM for permanent storage of startup instructions. Other components described are hard drives for long-term storage, expansion cards for additional functions, power supply for electricity, and input/output ports and drives for connecting to other devices and media.
Memory is divided into primary and secondary memory. Primary memory directly interacts with the CPU and includes ROM and RAM. ROM stores initial startup instructions and cannot be changed, while RAM stores active programs and data and comes in volatile DRAM and non-volatile SRAM types. Secondary memory like hard disks store data permanently and have greater storage than primary memory.
The document discusses different types of computer memory. It describes cache memory as very high speed memory between the CPU and main memory used to store frequently accessed data and programs. Primary/main memory is volatile semiconductor memory that holds currently running programs and data. RAM and ROM are types of main memory. RAM is read/write memory that stores data temporarily while power is on, while ROM is read-only memory that permanently stores basic input/output instructions. The document outlines characteristics and types of each memory including static RAM, dynamic RAM, programmable ROM, erasable programmable ROM, and electrically erasable programmable ROM.
Computer memory can be divided into internal and external memory. Internal memory includes cache and main memory, while external memory includes magnetic disks and optical disks. Memory types include RAM, ROM, SRAM, DRAM, PROM, EPROM, and EEPROM. RAM is volatile and used for main memory, while ROM is non-volatile and used to store permanent instructions. Cache memory is very fast memory between the CPU and main memory used to store frequently accessed data and instructions from main memory. Virtual memory allows programs to exceed physical memory size by storing unused portions on external memory.
Primary storage devices include cache memory and RAM that are located inside the computer. Cache memory temporarily stores frequently used data closer to the CPU than RAM for faster access. RAM holds programs and data being actively processed. ROM is non-volatile memory that stores critical instructions and cannot be changed by the user, including BIOS programs. Different types of ROM are MROM, PROM, EPROM, and EEPROM, which can be electrically erased and reprogrammed unlike MROM and PROM.
There are two main types of computer memory: volatile and non-volatile. Volatile memory, like RAM, loses its stored data when power is removed but is fast, while non-volatile memory, like ROM, retains data without power but is slower. RAM is the primary memory for running programs and comes in types like SDRAM, DDR SDRAM, DDR2 SDRAM, and DDR3 SDRAM that have faster data transfer speeds. Caches and registers are even faster but smaller memory types close to the CPU. Non-volatile memory includes ROM for long-term storage and flash memory for rewritable storage.
Memory and storage devices allow computers to store data and instructions. There are two main types of memory - primary and secondary. Primary memory (RAM, ROM, cache) is fast but volatile, while secondary memory (hard disks, SSDs, tapes) is slower but provides non-volatile storage. Storage technologies include magnetic, optical, and solid state, each with their own characteristics around performance, capacity, volatility, mutability and accessibility. Efficient memory management by the operating system is important to optimize system performance.
RAM allows stored data to be accessed randomly in any order. It is a type of volatile memory that does not permanently store data and loses its contents when powered off. There are two main types of RAM: static RAM and dynamic RAM. Dynamic RAM needs to be refreshed to maintain its contents while static RAM does not. RAM technologies have evolved from FPM DRAM to EDO DRAM, SDRAM, DDR SDRAM, and RDRAM to increase bandwidth and transfer rates. The memory hierarchy includes CPU registers, cache memory levels L1-L3, main memory, virtual memory, and storage. Future RAM technologies aim to be smaller, faster, and cheaper through innovations like RRAM and Z-RAM.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...Leonel Morgado
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
2. Computer Memory
Memory refers to the electronic holding place for
instructions and data where the processor can reach
quickly.
a) PRIMARY Memory(to store data and hold the
intermediate results) Ex:RAM,ROM
b) SECONDARY Memory(to store the output)
Ex:Hardisk
3. Primary memory
• Primary memory holds only those data and
instructions on which the computer is currently
working.
• It has a limited capacity and data is lost when power
is switched off.
• It is generally made up of semiconductor device.
These memories are not as fast as registers.
• The data and instruction required to be processed
resides in the main memory. It is divided into two
subcategories RAM and ROM.
4. Secondary Memory
• This type of memory is also known as external
memory or non-volatile. It is slower than the main
memory.
• These are used for storing data/information
permanently. CPU directly does not access these
memories, instead they are accessed via input-
output routines.
• The contents of secondary memories are first
transferred to the main memory, and then the CPU
can access it. For example, disk, CD-ROM, DVD,
etc.
5. Memory Representation
• Digital computers work on only two states: ON (1)
and OFF (0).
• These two values presented by two different
voltages within the circuit.
• Each of these values (either o or 1) is called a
binary digit or bit and can be considered a symbol
for a piece of information
6. Various units used to measure computer memory are as
follows:
1. Bit
2. Byte
3. Kilobyte
4. Megabyte
5. Gigabyte
6. Terabyte
7. • Bit: It is the smallest unit of data on a machine and
a single bit can hold only one of two values: 0 or 1.
Bit is represented by a lower case b.
• Byte: A unit of eight bits is known as a byte. Hence,
a byte is able to contain any binary number between
00000000 and 11111111. It is represented by an
upper case B.
• Kilobyte: In a decimal system, kilo stands for 1000,
but in a binary system, kilo refers to 1024.
Therefore, a kilobyte is equal to 1024 bytes. It is
usually represented as KB.
8. • Megabyte: It comprises 1024 kilobytes, or
1,048,576 bytes. However, since this number is
hard to remember, a megabyte can be thought of as
a million bytes. Megabyte is the standard unit of
measurement for RAM and is represented as MB.
• Gigabyte: It consists of 1024 megabytes
(1,073,741,824 bytes). It is the standard unit of
measurement for hard disks and is often represented
as GB.
• Terabyte: It refers to 1024 gigabytes. Often
represented as TB, terabyte memory is usually
associated with super computers only
10. Memory Hierarchy
• The processor is the "brain" of the computer where
all the essential computing takes place.
• The memory in a computer system is of three
fundamental types:
Internal Processor Memory:
This memory is placed within the CPU (processor) or
is attached to a special fast bus.
Internal memory usually includes cache memory and
special registers, both of which can be directly
accessed by the processor.
This memory is used for temporary storage of data and
instructions on which the CPU is currently working.
11. • It is generally used to compensate for the speed gap
between the primary memory and the processor
12. Primary Memory:
Random access memory (RAM) and read only
memory (ROM) fall under the category of the
primary memory, also known as main memory.
Every computer comes with a small amount of
ROM, which contains the boot firmware (called
BIOS). This holds enough information to enable
computer to check its hardware and load its
operating system into its RAM at time of system
booting.
13. • RAM is the place where the computer temporarily
stores its operating system, application programs and
current data so that the computer's processor can reach
them quickly and easily.
• It is volatile in nature, that is, when the power is switched
off; the data in this memory are lost.
• Unlike RAM, ROM is non-volatile. Even when the
computer is switched off, the contents of the ROM
remain available.
14. Secondary Memory:
• Also known as auxiliary memory, secondary memory
• provides backup storage for instructions (computer
programs) and data.
• The most common used secondary storage devices are
magnetic disk and magnetic tapes.
• These are least expensive and also have much larger
storage capacity than the primary memory. The
instructions and data stored on secondary storage
devices are permanent nature.
15. • Secondary Memory can only be removed if the
user wants it so or if the device is destroy
Secondary memory can also be used as overflow
memory (also known as virtual memory), when
the capacity of the main memory is surpassed.
[Virtual memory is a memory management
capability of an OS that uses hardware and
software to allow a computer to compensate for
physical memory shortages by temporarily
transferring data from random
access memory (RAM) to disk storage.]
19. RANDOM ACCESS MEMORY
• RAM is like the computer's scratch pad. It allows the
computer to store data for immediate manipulation and to
keep track of what is currently being processed
• It is the place in a computer where the operating system,
application programs and data in current use are kept they
can be accessed quickly by the computer's processor
• RAM is much faster to read from and write to than
the other kinds of storage in a computer, like the hard
disk or floppy disk
20. RANDOM ACCESS MEMORY
• However, the data in RAM stay there only as long as the
computer is running When the computer is turned off,
RAM loses all its contents. When the computer is turned
on again, operating system and other files are once again
loaded into RAM.
• When an application ram is started, the computer loads it
into RAM and does all the processing there. This allows
the computer to run the application faster. Any new
information that is created is kept in land since RAM is
volatile in nature, one needs to continuously save the new
information to the hard disk.
21. • Main memory is much faster than secondary memory
• The process of putting things that the CPU needs in a
single place from where it can get them quickly
22.
23. Types of RAM
• Static RAM (SRAM)
– The word "static" indicates that the memory retains its
contents as long as power is being supplied. However,
as soon as the power goes down, the data are lost.
– This makes SRAM a volatile memory as opposed to
ROM. SRAM does not need to be "refreshed" (pulse
of current through all the memory cells) periodically. It
is very fast but much more expensive than DRAM
(Dynamic RAM). SRAM is often used as cache
memory due to its high speed.
24. Dynamic RAM (DRAM)
• It is named so because it is very unstable. The data
continue to move in and out of the memory as
long as power is available.
• Unlike SRAM, DRAM must be continually
refreshed in order to maintain the data.
• This is done by placing the memory on a refresh
circuit that rewrites the data several hundred times
per second. DRAM is used for most system
memory because it inexpensive and small
25. • The primary difference between SRAM and DRAM is
that the life of the data they store.
• SRAM retains its contents as long as electrical power is
supplied to the chip. If the power is turned off its contents
are lost.
• On the other hand, DRAM must be continuously refreshed
after about every 15 microseconds.
• This is true even when power is supplied constantly.
• SRAM chips are not as dense as DRAM chips, that is, the
total number of cells in the SRAM chip is less than that on
DRAM chip.
• SRAM is beneficial because it is fast, has low latency(quick
response for requset) and does not need to be refreshed.
26. • SRAM is large and expensive and require
more power to operate and produce lot of
heat
• DRAM is simple and space efficient.
• SRAM is useful for low amount of memory
27. READ ONLY MEMORY
• Just as a human being needs instructions from the brain
to perform actions in a certain event a computer also needs
special instructions every time it is started.
• This is required because during the start up operation,
the main memory of the computer is empty due to its
volatile property so there have to be some instructions
(special boot programs) stored in a special chip that could
enable the computer system to perform start up operations
and transfer the control to the operating system.
28. • This special chip, where the start up instructions
are stored, is called ROM. It is non-volatile in
nature, that is, its contents are not lost when the
power is switched off
• The data and instructions stored in ROM can only be
read and used but cannot be altered, thereby making
ROM much safer and secure than RAM.
• ROM chips are used not only in the computer but
also in other electronic items like washing machines
and microwave ovens
29. Types of ROM
Memories in the ROM family are distinguished by the
methods used to write data on them and the number of
times they can be rewritten
• Masked ROM
• Programmable ROM(PROM)
• Erasable Programmable ROM(EPROM)
• Electrically Erasable Programmable ROM(EEPROM)
• Flash ROM
30. Masked ROM
• The very first ROMs, known as masked ROMs,
were hardwired devices that contained a pre-
programmed set of data or instructions.
• The contents of such ROMs had to be specified
before chip production so the actual data could be
used to arrange the transistors inside the chip.
31. ProgrammableROM(PROM)
• Creating a ROM chip from scratch is a time consuming and an
expensive process. For this reason, developers created a type of
ROM known as programmable read only memory (PROM), which
can be programmed.
• Blank PROM chips can be bought economically and coded by the
users with the help of a special device known as PROM-
programmer.
• However, once a PROM has been programmed, its contents can
never be changed. As a result, PROM is also known as one-time
programmable (OTP) device.
• Like other ROMs, PROM is also non-volatile. However, it is more
delicate than other ROMs as a jolt of static electricity can easily
cause the fuses in the PROM to burn out, thus changing the bit
pattern from 1 to O
32. • An EPROM is programmed in exactly the same
manner as a PROM.
• However, unlike PROM, an EPROM can be erased and
reprogrammed repeatedly. It can be erased by simply
exposing the device to a strong source of ultraviolet
light for a certain amount of time.
• Note that an EPROM eraser is not selective; it will
erase the entire EPROM. Although EPROM is more
expensive than PROM, its ability to be reprogrammed
makes it more useful.
Erasable Programmable ROM
(EPROM):
33. • This type of ROM can be erased by an electrical
charge and then written to by using slightly higher-
than- normal voltage.
• EEPROM can be erased one byte at a time, rather
than erasing the entire chip with ultraviolet light.
• Hence, the process of reprogramming is flexible, but
slow. Also, changing the contents does not require any
additional committed equipment.
Electrically Erasable
Programmable ROM (EEPROM):
34. Flash ROM
• A flash ROM also called flash BIOS or flash memory,
is a type constantly powered non-volatile memory that
can be erased and reprogrammed in blocks.
• 1t is a variation of EEPROM, which, unlike flash
memory, is erased rewritten at the byte level. Flash
memory is often used to hold the control code as the
BIOS in a personal computer.
• When BIOS needs to be changed or rewritten, the
flash memory can be written in block (rather than
byte) sizes, thus making it easier to update.
35. RAM, ROM AND CPU INTERACTION
The most essential part of computer processing is the
memory. From the moment computer is turned ON and until
it is shut down, the CPU constantly uses memory.
Step 1: The computer is switched ON.
Step 2: CPU loads data and instructions from ROM and
checks whether all the major components like processor and
hard disk are functioning properly.
Step 3: CPU loads BIOS (basic input/output system) from
ROM to determine the machine's fundamental configuration
and environment.
36. Step 4:CPU loads the operating system from the secondary
storage (hard disk) into RAM. This allows the CPU immediate
access to the operating system, which enhances the
performance and functionality of the overall system.
Step 5: When an application is opened, it is loaded into RAM
and any file that is opened for Use in that application is also
loaded into RAM.
Step 6: After processing, when the user saves the file and
closes the respective application, the file is written to the
specified location on the secondary storage device. After that
the file(s) and the application are "flushed out" from the RAM.
37. The CPU will read write data and instructions to the
Computer is in OFF state, ROM contains
data But RAM does not
When computer is turned ON the CPU reads the
data and instructions from the ROM