Hardware

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Hardware

• Overview of the CPU and its parts, memory, binary
  codes, peripheral devices, other system components

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Schematic model of a computer system
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COMPUTATION CYCLE

• I-cycle
• E-cycle

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CPU

• ALU
• control unit
• registers
• data buses
• Moores law transistor density doubles every 18
  months (today 100 M/chip)

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HOW ARE THEY INTERCONNECTED?

• Through the system bus

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Memory

• Main memory
• RAM
• EDO RAM (Extended Data Out RAM)
• DRAM (Dynamic RAM faster)
• SDRAM (Synchronous DRAM even faster)
• ROM
• PROM (WORM)
• EPROM
• PCMCIA cards (Personal Computer Memory Card
  International Association)
• Flash memory non-volatile chip memory sticks

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Memory types
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Cache memory Easily accessible fast memory
for frequently used data located near the CPU
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BINARY NUMBERS vs. BINARY CODES

• Binary numbers
• Standard binary codes
• ASCII (American Std. Code for Information
  Interchange)
• EBCDIC (Extended Binary Coded Decimal Interchange
  Code)

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Abbreviations numbers of bytes they represent
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SPEED OF COMPUTERS

• CISC (Complex Instruction Set Computing)
• Using ALL instructions in the CPU (many PCs)
• RISC (Reduced Instruction Set Computing)
• Using only the necessary instructions in the CPU
  (faster than CISC)
• VLIW (Very Long Instruction Word)
• Including more words per instructions. (faster
  than RISC)
• Parallel processing (more processors)

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Classes of computer systems
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Types of storage devices

• Magnetic disks (random access)
• hard discs
• flexible disks
• Memory sticks (random)
• Optical disks (random)
• Magnetic tapes (sequential)

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Hard disks

• track/surface/cylinder concept
• read-write head column
• head-surface clearance
• removable hard disks
• data access times
• seek time
• rotation time
• transfer time

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Hard disks (contd)

• physical sizes of hard disks
• storage capacities of hard disks
• will a disk twice the size store twice the data?

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Flexible disks

• Sizes
• Storage capacities
• HD diskettes 1.44 MB
• ZIP disks 100, 250, 750 MB
• Memory sticks 512 MB
• Formatting
• Access times for some types of disks
• large DASD 1-10 msec
• winchester 10-20 msec
• floppy 175-300 msec
• optical 100-500 msec

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Other disk technologies

• Floptical disks (optical seek/magnetic store)
• write erase!
• Cache disk (not a disk it is a fast memory)
• RAID (Redundant Arrays of Inexpensive Disks)
• Expandable storage devices
• Disk cartridges
• ZIP
• Memory sticks

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Other disk technologies (contd)

• Optical disks, CDs (3-650 MB)
• WORM optical disks
• MO (Magneto-Optical) disks
• Magnetic/CDROM technologies combined
• write erase!!
• DVD (17 gig a larger capacity CD-ROM)
• Indexed organization of disks for storage and
  retrieval
• SAN (Storage Area Networks) networked storage
  devices

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Tapes

• Sequential access
• Method of storage and parity
• Tape cartridges Purpose and utility of tape
  storage
• Blocking and density
• Capacity about 10 GB

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Some features of some secondary storage devices
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Input devices

• Keyboard
• Mouse
• Bar code scanner
• RFID receivers
• Voice recognition
• MICR reader
• OCR

• Pen input
• Touch screen
• Iris scanners
• Magnetic card scanners
• Image scanners
• ATM (I/O)

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MICR on checks
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Output devices

• Monitors
• CRT
• LCD
• Printers
• Plotters
• Sound
• Speakers
• MP3

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Standards which ensure seamless operation
interfacing

• Musical instruments digital standards
• Multimedia standards
• Plug and play standards
• Small Computer System Interface standards (SCSI)
• Personal Computer Memory Card International
  Association (PCMCIA) standards

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End Hardware