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IT Systems In and Out EN230-1

IT Systems In and Out EN230-1. Justin Champion C208 – 3273 www.staffs.ac.uk/personel/engineering_and_technology/jjc1. IT Systems. Contents What is I/O Motherboards Types of I/O. IT Systems. I/O ?? Stands for Input/Output

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IT Systems In and Out EN230-1

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  1. IT SystemsIn and OutEN230-1 Justin Champion C208 – 3273 www.staffs.ac.uk/personel/engineering_and_technology/jjc1

  2. IT Systems • Contents • What is I/O • Motherboards • Types of I/O

  3. IT Systems • I/O ?? • Stands for Input/Output • A large number of devices allow us to send information into the processor and receive it afterwards • Hard Disks • Ram • CD-Writers • Keyboards • Printers • Monitors • Etc, etc

  4. IT Systems • A number of standards are defined for I/O • Standards are required so that any device which meets that standard can communicate with any other device • USB • SCSI • RAM (Discussed last week) • IDE • Serial • Parallel • FireWire

  5. IT Systems • These standards are being used to get information to the processor • Once at the processor this information can then be acted upon. • To allow all of these devices to communicate with the processor they must be connected together • The motherboard allows all of the devices to connect together for communications

  6. IT Systems • Motherboard • This is a integrated circuit which allows circuits to be developed between all of the devices attached

  7. IT Systems • Bus? • The bus is the way that data is moved around the motherboard • Each part communicates with the System bus

  8. IT Systems • System Bus consists of • Data Bus • The data that is transferred at once • The bigger the more information which can be transferred in one cycle • Control Bus • Carries control signal so that all devices now the current operation state • Address Bus • Indicates where the data is intended for • The bigger the more device that can be attached

  9. IT Systems • Data Bus • The data bus for efficiency should be able to carry the maximum amount of data the processor can deal with • 8088 • 80286 • 24 Bit address bus, maximum 16Mb of memory • 80386 & 80486 • 32 Address Bus, 4 Gb of memory • Intel Itanium - 64 bit • 64 Address Bus, Sixteen exabytes ???

  10. IT Systems • Storage Memory Sizes • Bit – 0 or 1 • Byte – 8 * bits • KiloByte – 1024 * Bytes • MegaByte - 1024 * Kilobytes • GigaByte - 1024 * MegaByte • TeraByte - 1024* GigaByte • Petayte - 1024* TeraByte • Exabyte - 1024* PetaByte • ZettaByte - 1024* ExaByte • YottaByte - 1024* ZetaByte or 1024 bytes

  11. IT Systems • BIOS • Basic Input/Output System (BIOS) • This is a piece of software which is written into the motherboard of your PC • It has just the knowledge to carry out a number of actions before handing over to the operating system • Power on Self Test (POST) • Checks all components are working correctly • Loads controls for • Keyboard • Disk drives (hard disk and floppy) • Serial communications • VGA basic display

  12. IT Systems • Hard Disc • The primary permanent storage area for a PC • A hard disc operates by changing the magnetic properties of the surface of a disc • The magnetic poles are changed in one bit to indicate either a 0 or a 1 • A arm is then moved across the platter which contains the bits to read back or write to a specific part of the hard disc • The platter is made up of sectors and tracks • These are then made up into clusters • The size of the cluster depends on the OS computer.howstuffworks.com/hard-disk3.htm, 2003

  13. IT Systems • Hard Disc • Cluster • When you write data to a cluster the entire cluster is used • Even if the file does not fill the cluster • This can be seen in this picture from win2000 • File size and size on disc

  14. IDE Integrated Drive Electronics (IDE) Common speeds are • UDMA33 = 33 Mbps • UDMA100 = 100 Mbps • IDE interfaces • Maximum of 2 devices per controller • These drives are cheap and mass produced • Maximum cable length of 48cm • Higher system costs as the controller requires CPU time • Are useful all uses with the exception of very intensive disk usage

  15. SCSI • Small Computer System Interface (SCSI) • Commonly considered to be the faster drives • Fastest specification is • Ultra 3 SCSI 240 Mbps, but this is not widely available • Most SCSI drives are similar in speed to IDE • Interface • Can cope with 8 devices attached to it • Can buffer instruction sent to the device • Very low CPU overhead for instructions typically 5% • Maximum cable length of 12 Metres • These drives are expensive! • Mostly used today on high end servers, where a number of drives needs to be connected at any time

  16. Serial • Serial • Is the sending of one bit of data at a time • This gives the advantage of only one cable being required for transmission • They are able to send duplex data • Duplex indicates that data can be sent and received at the same time. • This is carried out by transmitting on a different cable than receiving upon • Pin 2 transmits data and pin 3 receives data • Standard serial ports can received data at 115 Kbps (using the RS232 standard)

  17. Serial 9 Pin serial port

  18. Serial • Serial • Traditional serial connection is through RS-232 and its successors • Newer standards are available • RS-442 • Allows faster speeds and longer connection cables, 4000 ft at 100 Kbps or a maximum speed of 1.5 Mbps with a shorter cable • RS-485 • Allows up to 16 devices daisy chained together to communicate • Similar speeds but this medium is shared like Ethernet

  19. Serial • Serial • Traditionally used for Modem communications • Still widely used a lot of handheld devices use serial communications ports.

  20. Serial • Parallel – IEEE 1284 standards • Unlike serial uses 8 wires at once • This allows 1 byte at a time to sent over the cable • Standard Parallel Port (SPP) • 100 Kbps • Enhanced Parallel Port (EPP) • 500Kbps to 2 Mbps

  21. Serial & Parallel • Parallel devices current uses • Printers • External Zip drives • External CD drives • Data Transfers

  22. Universal Serial Bus (USB) • Universal Serial Bus (USB) • Standards • 1.0 – 12 Mbps • 2.0 – 480 Mbps • Maximum of 127 devices daisy chained together • All share a single interrupt (IRQ) • These devices can supply a small amount of electricity • 500 Milliamps at 5 volts • Now available for all operating systems • Including Linux

  23. Universal Serial Bus (USB) • Universal Serial Bus (USB) • Devices are • Hot swappable • Can be put to sleep • Data can be transferred in different methods • Interrupt based • Small amounts of data to be transferred • Bulk • Large amounts of data like a scanner • Isochronous • Continuous data transfer like a web cam • Data transfer rates are guaranteed for the devices

  24. Firewire • IEEE-1394 • High-speed serial bus, originally called Firewire, developed by Apple in 1995 • I-link used by Sony • Offers data rates of 100 - 400 Mbps • Allows a maximum 63 nodes to be connected • A maximum of 72 metres of cable between the host and the device (using a daisy chain) • The cabling can provide the power to the device if required • 40 volts with 1.5 amps maximum • Mainly used for digital video transfer where this throughput is required

  25. IT Systems • Summary of what we have discussed • Motherboard • Processor types • I/O Types • Hard disc • USB • Serial • FireWire

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