The major hardware components of a computer system include the central processing unit (CPU), auxiliary storage, input devices, and output devices. The CPU contains the arithmetic logic unit (ALU) for processing data and the control unit for managing data flow. Main memory temporarily stores programs and data required by the CPU. Common input devices include keyboards and mice, while common output devices include monitors and printers.

1. Major Hardware Components ofMajor Hardware Components of
a Computer Systema Computer System
• Central Processing UnitCentral Processing Unit
• Auxiliary StorageAuxiliary Storage
• Input DevicesInput Devices
• Output DevicesOutput Devices

2. Central Processing UnitCentral Processing Unit
• Arithmetic/Logic Unit (ALU): processes dataArithmetic/Logic Unit (ALU): processes data
arithmetically (addition, subtraction,arithmetically (addition, subtraction,
multiplication, division) or logically (greater than,multiplication, division) or logically (greater than,
less than, equal to)less than, equal to)
• Control Unit: works with the operating system toControl Unit: works with the operating system to
move data between auxiliary storage and mainmove data between auxiliary storage and main
memory; and between main memory and the ALUmemory; and between main memory and the ALU
• Main Memory: contains both program instructionsMain Memory: contains both program instructions
and the data that is required.and the data that is required.
• A single machine can have multiple CPUs toA single machine can have multiple CPUs to
share processing tasks (co-processors,share processing tasks (co-processors,
multiprocessing), but each CPU can execute onlymultiprocessing), but each CPU can execute only
a single task.a single task.

3. Inside the System UnitInside the System Unit
• Main component: motherboardMain component: motherboard
– Circuit board that “houses” integrated circuitsCircuit board that “houses” integrated circuits
(microscopic elements … wires, transistors,(microscopic elements … wires, transistors,
etc…) required to make the digital pulse flowetc…) required to make the digital pulse flow
inside of the computer. Pulses flow frominside of the computer. Pulses flow from
component to component via the “bus”component to component via the “bus”
– Some microcomputers contain a special localSome microcomputers contain a special local
bus (VESA or PCI) which increase data transferbus (VESA or PCI) which increase data transfer
rates to the display and/or storage devicesrates to the display and/or storage devices

4. Motherboard (cont.)Motherboard (cont.)
– Attachments to the motherboard include:Attachments to the motherboard include:
• Main Memory: types of main memory include:Main Memory: types of main memory include:
– RAM - temporary (includes virtual memory storage). Include RAMRAM - temporary (includes virtual memory storage). Include RAM
cachecache
– ROM - permanentROM - permanent
– CMOS - semipermanent battery poweredCMOS - semipermanent battery powered
» Memory chips attach with either a DIP (dual inline pin - old PCs)Memory chips attach with either a DIP (dual inline pin - old PCs)
or as a SIMM (single inline memory module) boardor as a SIMM (single inline memory module) board
– When add main memory, make sure add-on chips are compatibleWhen add main memory, make sure add-on chips are compatible
• Real time clock (current date and time)Real time clock (current date and time)
• Microprocessor or CPU (central processing unit)Microprocessor or CPU (central processing unit)
– Control Unit: traffic cop portion of the CPUControl Unit: traffic cop portion of the CPU
– ALU: arithmetic logic unit processes all math and logical operationsALU: arithmetic logic unit processes all math and logical operations
performed by the computerperformed by the computer

5. • Expansion slots/add on boards - allow “cards” that attachExpansion slots/add on boards - allow “cards” that attach
various peripheral devices to the motherboardvarious peripheral devices to the motherboard
– monitors, hard drive, internal fax/modem, network cards,etcmonitors, hard drive, internal fax/modem, network cards,etc
– PCMCIA slots: special slots developed for laptops to attachPCMCIA slots: special slots developed for laptops to attach
devices and add on RAMdevices and add on RAM
• Expansion devices may provide an external “port” which youExpansion devices may provide an external “port” which you
connect a cable to. Device ports will either be from an internalconnect a cable to. Device ports will either be from an internal
or external bay in the system unit.or external bay in the system unit.
– Serial Port: transmits data one bit at a time (modem)Serial Port: transmits data one bit at a time (modem)
– Parallel Port: transmits 8 bits simultaneously (printers, backupParallel Port: transmits 8 bits simultaneously (printers, backup
devices, etc.)devices, etc.)
– SCSI Port: allows several devices to be chained together andSCSI Port: allows several devices to be chained together and
connected through a single SCSI (small computer systemconnected through a single SCSI (small computer system
interface)interface)
– MIDI Port: musical instrument digital interfaceMIDI Port: musical instrument digital interface
MotherboardMotherboard (cont.)(cont.)

6. Main MemoryMain Memory
• Random Access Memory (RAM):Random Access Memory (RAM): allows dataallows data
and instructions to be accessed randomly from anyand instructions to be accessed randomly from any
memory location (address). Primary storage.memory location (address). Primary storage.
– Volatile - lost when power is turned offVolatile - lost when power is turned off
• Read Only Memory (ROM): usually containsRead Only Memory (ROM): usually contains
programs that help the computer system operate:programs that help the computer system operate:
– can only be read: cannot be written to or altered by thecan only be read: cannot be written to or altered by the
user (usually)user (usually)
– ROM is not volatileROM is not volatile

7. Main MemoryMain Memory
• Data and instructions are stored asData and instructions are stored as BITS (binaryBITS (binary
digits)digits). Everything from our world is translated. Everything from our world is translated
into a computer recognizable format calledinto a computer recognizable format called binarybinary
(zeros or ones)(zeros or ones)
– The combination of binary digits represents our lettersThe combination of binary digits represents our letters
or numbers. One character represented is equal to aor numbers. One character represented is equal to a
byte.byte.
• Memory capacity is measured in bytes. Today’sMemory capacity is measured in bytes. Today’s
most common measurement ismost common measurement is megabytesmegabytes
Kilo = 1,000 (KB) ThousandKilo = 1,000 (KB) Thousand
Mega = 1,000,000 (MB) MillionMega = 1,000,000 (MB) Million
Giga = 1,000,000,000 (GB) BillionGiga = 1,000,000,000 (GB) Billion
• Bytes are composed using either theBytes are composed using either the ASCIIASCII
coding system (7 bits = character) orcoding system (7 bits = character) or EBCDICEBCDIC (8(8
bits = character)bits = character)

8. Microprocessor FamiliesMicroprocessor Families
• Intel (IBM) and Motorola (MacintoshIntel (IBM) and Motorola (Macintosh
68000) two main manufacturers68000) two main manufacturers
• Microprocessors are “families” - upwardMicroprocessors are “families” - upward
increases in speed (early SX vs DX chips)increases in speed (early SX vs DX chips)
• Increase in bus capacity indicates a newIncrease in bus capacity indicates a new
generationgeneration

9. The Boot ProcessThe Boot Process
• When you turn your computer on, the followingWhen you turn your computer on, the following
activities happen:activities happen:
– Power is sent to the internal fan and the motherboardPower is sent to the internal fan and the motherboard
– The boot program stored inside of ROM activatesThe boot program stored inside of ROM activates
– The Power-On Self-Test (POST)runs and tests requiredThe Power-On Self-Test (POST)runs and tests required
system componentssystem components
– The operating system/environment is loadedThe operating system/environment is loaded
– Configuration and customization routines are executedConfiguration and customization routines are executed
which set your computer environmentwhich set your computer environment

10. Input/Output Peripheral DevicesInput/Output Peripheral Devices
• Badge ReaderBadge Reader
• Bar-code ReaderBar-code Reader
• Cartridge & cassetteCartridge & cassette
drivesdrives
• CD RomCD Rom
• Digital cameraDigital camera
• Digital tables & scannersDigital tables & scanners
• Keyboard, mouse, pensKeyboard, mouse, pens
• MICRMICR
• VoiceVoice
• OCROCR
• Touch screenTouch screen
• SASD & DASD drivesSASD & DASD drives
• PrintersPrinters
– Page vs line or characterPage vs line or character
printersprinters
– Impact vs nonimpactImpact vs nonimpact
• PlotterPlotter
• RoboticsRobotics
• Speech synthesizerSpeech synthesizer
• VDTVDT
• MicroformsMicroforms

11. StorageStorage
Required because main memory is limited, expensiveRequired because main memory is limited, expensive
and volatile.and volatile.
• Sequential Access Storage Devices (SASD):Sequential Access Storage Devices (SASD): data is storeddata is stored
in sequential order. Retrieval is also sequential.in sequential order. Retrieval is also sequential.
– Storage media is magnetic tape.Storage media is magnetic tape.
– Supports batch processing environmentSupports batch processing environment
– Excellent form of backupExcellent form of backup
• Direct Access Storage Devices (DASD):Direct Access Storage Devices (DASD): data can be storeddata can be stored
and retrieved randomly.and retrieved randomly.
– Storage capacity is referred to as density. How tightlyStorage capacity is referred to as density. How tightly
packed data is on the disk.packed data is on the disk.
– DASD is required for transaction processing.DASD is required for transaction processing.
• Memory capacity is measured in bytes. Today’s mostMemory capacity is measured in bytes. Today’s most
common measurement iscommon measurement is kilobytes,kilobytes, megabytes and gigabits.megabytes and gigabits.

12. Printer ConsiderationsPrinter Considerations
• Dot matrix - low price & inexpensive toDot matrix - low price & inexpensive to
operate. Lower quality. Impact - can printoperate. Lower quality. Impact - can print
carbon forms. Color option. Slow.carbon forms. Color option. Slow.
• Ink jet - moderate price & better output.Ink jet - moderate price & better output.
Color option. Nonimpact. Quieter.Color option. Nonimpact. Quieter.
• Laserjet - more expensive. Faster. HighLaserjet - more expensive. Faster. High
quality. Nonimpact.quality. Nonimpact.

13. Display ConsiderationsDisplay Considerations
• Screen size- diagonal measurement from corner toScreen size- diagonal measurement from corner to
corner. Popular sizes are 14”, 15” and 17”corner. Popular sizes are 14”, 15” and 17”
• Dot pitch - measure of image clarity. The smallerDot pitch - measure of image clarity. The smaller
the dot pitch, the crisper the image or resolution.the dot pitch, the crisper the image or resolution.
• Video adapters/cards impact image resolution andVideo adapters/cards impact image resolution and
display speed. Today, most monitors are Superdisplay speed. Today, most monitors are Super
VGA (1024 x 768)and use non-interlacedVGA (1024 x 768)and use non-interlaced
projection technology (flicker)projection technology (flicker)
• Laptop - liquid crystal display (LCD). PassiveLaptop - liquid crystal display (LCD). Passive
matrix vs active matrix screen (display methodmatrix vs active matrix screen (display method
which impacts image quality). Active matrix iswhich impacts image quality). Active matrix is
much better but more expensive and can havemuch better but more expensive and can have
problems.problems.

14. DASDDASD
• Floppy Disk:Floppy Disk: removable DASD. Most commonremovable DASD. Most common
density is 1.44Mb.density is 1.44Mb.
• Hard Disk:Hard Disk: usually don’t remove (but newerusually don’t remove (but newer
devices you can). Higher storage capacity thandevices you can). Higher storage capacity than
floppy disks. Faster access.floppy disks. Faster access.
– Winchester drive architecture is not removable.Winchester drive architecture is not removable.
– Can be drives that have removable disk platters.Can be drives that have removable disk platters.
– Optical disk: CD_ROM (read-only) Erasable opticalOptical disk: CD_ROM (read-only) Erasable optical
disk is also available. WORM - write once, read many.disk is also available. WORM - write once, read many.
– Flash memory: main memory on a card. Non volatile.Flash memory: main memory on a card. Non volatile.
PCMCIA card.PCMCIA card.

15. DASD cont.DASD cont.
• All data stored on DASD media is stored in pie-All data stored on DASD media is stored in pie-
shapedshaped sectorssectors that determines how much data isthat determines how much data is
moved into and out of main memory at a time.moved into and out of main memory at a time.
• Virtual storage:Virtual storage: operating system uses hard diskoperating system uses hard disk
drive as an extension of main memory.drive as an extension of main memory.
• Cache memory:Cache memory: operating system assumes thatoperating system assumes that
most data used by an application is accessed overmost data used by an application is accessed over
and over again. Cache is a special area in mainand over again. Cache is a special area in main
memory where such data is put instead of pagingmemory where such data is put instead of paging
it back and forth to DASD.it back and forth to DASD.

16. DASD contDASD cont
• WORM: write-once, read many. (CDWORM: write-once, read many. (CD
ROM). Also have rewriteable CD ROM.ROM). Also have rewriteable CD ROM.
• Floptical Disk: optical storage capacities onFloptical Disk: optical storage capacities on
floppy disk.floppy disk.
• DVD: Digital video diskDVD: Digital video disk
• Hierarchical Storage: use of many differentHierarchical Storage: use of many different
types of DASD & SASD devices to achievetypes of DASD & SASD devices to achieve
storage requirements.storage requirements.

17. Other considerations:Other considerations:
• Desktop vs Laptop - expansion slots andDesktop vs Laptop - expansion slots and
capabilitycapability
– Port replicators vs docking stationPort replicators vs docking station
– Pointing device. Track ball, touch pad, erase point.Pointing device. Track ball, touch pad, erase point.
– Power management & battery considerations (hotPower management & battery considerations (hot
swap)swap)
• Multimedia devices - sound cards, speakers andMultimedia devices - sound cards, speakers and
MPC standardsMPC standards
• Bundled softwareBundled software

18. Common File TypesCommon File Types
• Data Files: files of information created whenData Files: files of information created when
people use various types of softwarepeople use various types of software
• Executable Files: Types of systems files that areExecutable Files: Types of systems files that are
used by the computer to perform certain tasks.used by the computer to perform certain tasks.
With some executable files (.exe., .com, .bat) youWith some executable files (.exe., .com, .bat) you
can initiate the processing while with others thecan initiate the processing while with others the
computer initiates the process (.dll, .sys, .drv, etc.)computer initiates the process (.dll, .sys, .drv, etc.)
• You and yourYou and your AUTOEXEC.BATAUTOEXEC.BAT file.file.

19. Anatomy of a FilenameAnatomy of a Filename
• Rules for creating valid filenamesRules for creating valid filenames
(appropriate characters, length of names,(appropriate characters, length of names,
etc.) depends on the operating system beingetc.) depends on the operating system being
used.used.
• Components of a filename consist of:Components of a filename consist of:
C:/foldername/filename.extC:/foldername/filename.extDrive DesignationDrive Designation
Folder/subdirectoryFolder/subdirectory
namename
File name fromFile name from
youyou
File extensionFile extension
supplied by thesupplied by the
programprogram

20. File StorageFile Storage
• Logical StorageLogical Storage::
How you perceive that dataHow you perceive that data
is stored on an auxiliaryis stored on an auxiliary
storage mediastorage media
File/disk directoryFile/disk directory
No indication ofNo indication of
fragmentationfragmentation
• Physical StoragePhysical Storage
How data actuallyHow data actually
resides on yourresides on your
auxiliary storageauxiliary storage
mediamedia
File Allocation TableFile Allocation Table
(FAT)(FAT)
Fragmentation is normalFragmentation is normal

21. Measurements of Computer PowerMeasurements of Computer Power
• Clock speed:Clock speed: electronic pulses used toelectronic pulses used to
synchronize processing. Faster clock speeds resultsynchronize processing. Faster clock speeds result
in more operations in a give amount of time.in more operations in a give amount of time.
Measured inMeasured in megahertz (MHz).megahertz (MHz).
• Bus width:Bus width: determines how much data can bedetermines how much data can be
transferred at any one time.transferred at any one time. 16 bit, 32 bit, 64 bit.16 bit, 32 bit, 64 bit.
– IBM’s Microchannel (MCA) Architecture vs EISAIBM’s Microchannel (MCA) Architecture vs EISA
(open architecture)(open architecture)
• Word size:Word size: number of bits/bytes manipulated atnumber of bits/bytes manipulated at
once. Same as the bus width.once. Same as the bus width.
• Other determinants include main memoryOther determinants include main memory
capacity, MIPs.capacity, MIPs.
• This is not the same as throughput but it can affectThis is not the same as throughput but it can affect
throughput..throughput..