Power Supply

Usually provides 3.3, 5, and 12 volts.

Converts AC to DC for internal pc components.

Interrupts

• Every
  device in the PC must be assigned an interrupt.
• Two
  ISA devices cannot share an interrupt.
• Two
  PCI devices can share interrupts.
• A PCI
  device cannot share an interrupt with an ISA device.
• Because
  INT 2 and INT 9 are actually the same wire on the PIC chips, you assign
  either one to a device in the system, but you can’t assign both at the
  same time.
• Some
  system devices have interrupts assigned to them by default. Some of these
  can be changed or disabled; many cannot.
  IRQ 0 – System Timer  IRQ 5 – LPT2
  IRQ 1 – Keyboard                   IRQ
  6 – Floppy Drive
  IRQ 3 – COM 2                      IRQ
  7 – LPT1
  IRQ 4 – COM 1                     
• Interrupts
  0, 1, and 8 are hard-wired. Under no circumstances can you use these
  interrupts for any other device in the system.
• If a
  device with a default interrupt assignment isn’t installed in the system
  or it is disabled, you can use its interrupt for another device.

Hexadecimal -
Base 16 Numbering System

0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

Input/Output Address

I/O addresses allow communications between the devices in
the PC and the operating system.

• All
  devices must have an I/O address assigned.
• Most
  devices will use a range of I/O addresses.
• Devices
  must use unique I/O ports.

Default I/O port assignments:

• 0000h
  - DMA Controller
• 0020h
  - PIC 1
• 0030h
  - PIC 2
• 0040h
  - System Timer
• 0060h
  - Keyboard
• 0070h
  - CMOS Clock
• 00C0h
  - DMA Controller
• 00F0h
  - Math Co-processor
• 0170h
  - Secondary IDE Hard Disk Controller
• 01f0h
  - Primary IDE Hard Disk Controller
• 0200h
  - Joystick
• 0278h
  - LPT2
• 02E8h
  - COM4
• 02F8h
  - COM2
• 0378h
  - LPT1
• 03E8h
  - COM 3
• 03F0h
  - Floppy Disk Drive Controller
• 03F8h
  - COM1

Direct Memory Access
Channels

Common devices that need it:

• Sound
  boards
• Floppy
  diskette drives
• Hard
  disk drives

Common points:

• No two
  devices can use the same channel
• Modern
  systems use two cascaded DMA controllers. Just as we cascade two PICs
  together to get 16 interrupts, we can also cascade two DCCs together to
  get 8 DMA channels. Just as interrupt 2 and 9 are really the same
  interrupt due to cascading, DMA channels 0 and 4 are actually the same DMA
  channel.
• The
  floppy diskette drive in your system is assigned DMA channel 2 by default.

Plug and Play

You must have the following:

• A
  PnP-compatible BIOS
• A
  PnP-compatible device
• A
  PnP-compatible operating system

Hard Drives

The parameters that compose the drive geometry include the
following:

• Heads
  - The heads parameter refers to the number of read/write heads in the
  drive.
• Cylinders
  - A cylinder refers to the concentric parallel tracks on all sides of all
  platters in the hard disk drive. Imagine a hollow cylinder that penetrates
  down through all of the platters in a hard drive. Depending on how wide
  the cylinder is you can fit a certain number of progressively wider
  cylinders, beginning in the center of the platters and working your way
  outward to the edge, within the drive platters.
• Sectors
  Per Track – In addition to creating imaginary cylinders in the drive, you
  can also slice each platter up into imaginary pie-shaped wedges. The
  sectors per track parameter refers to the number of wedges the platters
  have been divided into.

SCSI

You can terminate SCSI devices the
following ways:

·       
Resistor Packs – Resistor packs are inserted in
the SCSI device’s circuit board to enable termination.

·       
Jumpers – A shaunted jumper is frequently used
to enable termination on the device.

·       
SCSI controller boards usually include a
software setup program run from the controller boards BIOS that can be used to
turn termination off and on.

·       
Active Termination – Many SCSI devices use
active termination. With active termination, the device checks to see if it’s
the last device on the chain. If it is, it automatically enables the
terminating resistor.

Questions:

What type of memory
is used to create the CPU cache?

Cache memory uses a special type of RAM called static ram.

Which type of memory
is used in 184-pin DIMM modules?

184-Pin DIMM modules use DDR-SDRAM memory.

Which PCI component
functions as an intermediary between the PCI bus and other expansion buses on
the motherboard?

The Southbridge
functions as an intermediary between the PCI bus and other expansion buses on
the system, such as the ISA bus.

You’re installing two
ISA expansion boards in an older PC system. Once is a sound board, the other a
network board. The system has IN 2 and IN 9 available. Can you assign these
interrupts to these two boards?

Because of the way the system’s PIC chips are cascaded, INT
2 and INT 9 are actually the same interrupt.

How many slave drives
can be configured on the Secondary IDE channel?

Any IDE channel has either 0 or 1 slave drive on the
channel. If no master is implemented on the channel, then no slave drives can
be implemented. If a master drive is implemented, then the channel can have on
slave drive.

Suppose you have a
SCI chain with four devices connected on an internal ribbon cable: An internal
hard drive (hd0) at the end of the cable followed by a second hard drive (hd1),
an internal CD drive (cd0), and then the SCSI controller (sc0). Which devices
should have termination enabled?

Because the first hard drive and the SCSI controller are
located at the ends of the SCSI chain, they must have termination enabled. No
devices in between should have termination enabled.