Information Processing Cycle
The sequence of events in processing information, which includes (1) input, (2)
processing, (3) output and (4) storage.
Input—entering data into the computer
Processing—performing operations on the data
Output—presenting the results.
Storage—saving data, programs, or output for future use.
1) INPUT:- The collection of raw data from the outside world so it can be put into an
information system. Putting the acquired data into the information system.
1. Examples: The payroll clerk collects workers' timecards so she knows how many
hours each person worked that week and types the hours from the timecards into
2. Conducting a survey of customer's opinions and then scanning the survey cards
with a card reader.
3. Collecting jokes for a joke book and typing jokes into a word processor.
4. Using a form on a website to collect visitors' opinions
Typical input devices:
Keyboards, mice, flatbed scanners, bar code readers, joysticks, digital data tablets (for
graphic drawing), electronic cash registers
2. PROCESSING:-CPU Processor - Central Processing Unit
A central processing unit (CPU), or sometimes simply processor, is the key component
in a digital computer capable of executing a program. It interprets computer program
instructions and processes data. CPUs provide the fundamental digital computer trait of
programmability, and are one of the necessary components found in computers of any
era, along with memory and input/output facilities. A CPU that is manufactured as a
single integrated circuit is usually known as a microprocessor. Beginning in the mid-1970s,
microprocessors of ever-increasing complexity and power gradually supplanted other
designs, and today the term "CPU" is usually applied to some type of microprocessor.
Microprocessor (CPU) Integrated circuit, also called a chip. The Brain of the computer
ALU: Arithmetic Logic Unit:
High speed calculator
Intel is the most popular chip
Categorized by model numbers
Higher model number=newer/faster chip
Speed of CPU is determined by clock speed
Higher the clock speed, faster the computer
Speed is measured in megahertz (MHz)
Megahertz: Clock Speed of the processor (100
MHz = 100 million cycles/second)
Memory or RAM
Next most critical element of a processing hardware is RAM, often referred to as
"primary storage" or "main memory". Random Access Memory (RAM) receives and
temporarily stores data and program instructions from the CPU This data bank
communicates with the CPU, constantly exchanging information and constantly
changing as long as the computer is on
RAM is an active, electronic state. When the power is on, RAM retains data. When the
computer is turned off, all data in RAM is erased unless you have saved it to some mass
storage device. Each time the computer boots, the computer goes through it's startup
routine and lastly loads operating system instructions into ram
Random Access Memory (RAM) is the workhorse behind the performance of your
computer. Working as a foot soldier for your processor, RAM temporarily stores
information from your operating system, applications, and data in current use. This gives
your processor easy access to the critical information that makes your programs run.
The amount of RAM you have determines how many programs can be executed at one
time and how much data can be readily available to a program. It also determines how
quickly your applications perform and how many applications you can easily toggle
between at one time. Simply put, the more RAM you have, the more programs you can
run smoothly and simultaneously.
To determine how much RAM you need, factor in the demands of the applications you
want to run simultaneously as well as the operating system (512 MB of RAM is
recommended by Microsoft as minimum for operation of Windows) Then keep in mind
that you'll inevitably add new applications and create new files, and add accordingly.
Types of RAM
DRAM (Dynamic RAM) This is the most common type of computer memory.
DRAM needs refreshing and is refreshed hundreds of times each second in order
to retain data. During recharging it cannot be accessed by the CPS
SRAM (Static RAM) SRAM is approximately 5 times faster (and twice as
expensive, as DRAM). It does not have to be constantly refreshed. Because of its
lower cost and smaller size, DRAM is preferred for the main memory, while
SRAM is used primarily for cache memory.
SDRAM (synchronous dynamic RAM) is the standard memory offering in the PC
industry and is faster than DRAM because it's synchronized to the system clock. .
It is designed for mainstream home and business applications, email, and basic
audio and video streaming. It provides single-channel memory and is available
on our mainstream and value desktop system.
DDR SDRAM (double data rate synchronous dynamic RAM) takes all the
features of ordinary SDRAM and increases the frequency bandwidth to improve
system performance and speed.
RDRAM (Rambus dynamic RAM) is able to load a new stream of data before the
previous stream has completed, resulting in faster access speeds. The RDRAM
memory features dual-channel processing which doubles data throughput to
further enhance performance. This type of memory is optimized for high-end
multimedia tasks involving video and audio. Dual Channel RDRAM is shipped on
our performance desktop systems powered by Pentium 4 processors
VRAM: Memory designed for storing the image to be displayed.
CACHE RAM is a small block of high-speed memory located between the
Processor and main memory and is used to store frequently requested data and
instructions. When the processor requests data, it will check in the cache first
The hierarchical arrangement of memory storage in current computer architectures is
called the memory hierarchy. It is designed to take advantage of memory locality in
computer programs. Each level of the hierarchy is of higher speed and lower latency,
and is of smaller size, than lower levels.
The memory hierarchy in most computers is as follows:
Processor registers – fastest possible access (usually 1 CPU cycle), only
hundreds of bytes in size
Level 1 (L1) cache – often accessed in just a few cycles, usually tens of kilobytes
Level 2 (L2) cache – higher latency than L1 by 2× to 10×, often 512 KiB or more
Level 3 (L3) cache – higher latency than L2, often several MB
Main memory (DRAM) – may take hundreds of cycles, but can be multiple
gigabytes. Access times may not be uniform.
In information processing, output is the process of transmitting the processing
Essentially, output is the presentation of any data exiting a computer system. This could
be in the form of printed paper, audio, video. In the medical industry this might include
CT scans or x-rays. Typically in computing, data is entered through various forms (input)
into a computer, the data is often manipulated, and then information is presented to a
Typical output devices:
Pixels: Images are created with dots of lights called picture elements, or pixels.
More pixels = higher resolution. Resolution is the maximum number of pixels the
monitor can display
Basic VGA is a pixel grid 640 X 480
Super VGA is 1,024 X 768
A video card, (also referred to as a graphics accelerator card, display adapter,
graphics card, and numerous other terms), is an item of personal computer
hardware whose function is to generate and output images to a display.
Laser - laser beams bond toner to paper
Ink jet - fine stream of ink
Dot Matrix - pins & ribbon
What else can you think of?
Storage, or mass storage refers to various techniques and devices for storing large
amounts of data. The earliest storage devices were punched paper cards, which were
used as early as 1804 to control silk-weaving looms. Modern mass storage devices
include all types of disk drives and tape drives. Mass storage is distinct from memory,
which refers to temporary storage areas within the computer. Unlike RAM memory,
mass storage devices retain data even when the computer is turned off.
The smallest unit of storage is a file that contains such data as a resume, letter, budget,
images or any one of the thousands of items that you may have saved for future
reference. Additionally, files can be executable program files, or system files reserved
for the operating system. Mass storage is measured in kilobytes (1,024 bytes),
megabytes (1,024 kilobytes), gigabytes (1,024 megabytes) and terabytes (1,024
Examples of some mass storage devices
Disk storage – hundreds of thousands of cycles latency, but very large
o Hard disks : Very fast and with more capacity than floppy disks, but also
more expensive. Some hard disk systems are portable (removable
cartridges), but most are not.
o Solid State Drives have no moving parts and utilize non-volatile memory
o Floppy Disks: (almost obsolete!)
Tertiary storage –
o Optical storage: Unlike floppy and hard disks, which use electromagnetism
to encode data, optical disk systems use a laser to read and write data.
Optical disks have very large storage capacity, but they are not as fast as
hard disks. Examples: CD, CD-R, CD-RW, DVD or DVD-R
o Tapes: Relatively inexpensive and can have very large storage capacities,
but they do not permit random access of data.
Flash Memory – faster than disk storage, with up to 4GB or more of data,
transferring (usually) over universal serial bus (USB)