Lecture


Addendum to Week 10

Boot Process/SCSI devices


System Clock creates pulses. Reminder of speeds and piezoelectric effect.

CPU initialized by bios after system pulses

CPU reads address FFF0H – startup address of Bios

This address tells the CPU to run a POST routine

POST tests the BIOS chip, memory, battery failure, CPU itself

POST then inventories the hardware devices, compares to the database

POST then tests and configures the video card and monitor

Beep codes indicate errors. Some manufacturers allow one beep in the beginning

One beep allowed for keyboard presence – show by holding down one key





Setup is then run if the operator requests it

Halts on errors unless changed in BIOS

Searches for OS on the hard drive – boot.ini part of MBR



Looks for OS in MBR, OS boot record then loads IO.sys or NTLOADER

Then MSdos.sys and config.sys or autoexec.bat



Batch files – creating virus, etc.


Discuss error messages and how to fix – No operating system found, no NTLOADER, etc. and how to fix.


Interrupts


First controller 0-7

Second controller cascaded through IRQ #2 of the first controller


System clock has to be IRQ 0 because everything in a computer works only after a clock pulse changes state.

32 bit address – device sets IRQ line by raising its voltage to 5 volts – this tells CPU that the device needs servicing in some fashion.

Northbridge is the memory controller chipset

Southbridge controls the expansion bus slots


Backward support of old (legacy devices)

Under Win98, device drivers and memory management was loaded into config.sys file. This file provides the backward support in the newer 2000 and XP the file is there even if not used)


Cold boot – when power switch is hit

Hot boot – when the Control, Alt , delete keys are depressed


PNP Plug and Play devices auto allocates IRQ’s and memory


File System

FAT File Allocation Table

NTFS New Technology File System

Root Directory

Sub directories

8.3 notations

Special characters – wildcards

After win95 255 character names If in DOS screen must use ~ or “ “ to access long file names


Boot Up


POST surveys hardware and assigns system resources

Searches for and initiates load of Operating System


Make up Emergency boot disks


Format /s adds system files to 98 disk

No bootable disks for XP


DOS Commands


Path prompt edit erase undelete defrag

CD attrib scandisk print type recover  deltree

Fdisk extract  diskcopy rmdir mkdir chkdsk del copy unformat




























Removable Media

Removable Drives


Can be internal or external

Advantages

Increase overall storage capacity

Easy to move large files between computers

Convenient medium for making backups

Easy to secure important files

Considerations when purchasing

Drop height

Half-life of the disk

Example types are:

Tape drives

ZIP drives

JAZZ drives

JUMP drives (old name for flash drives)


Tape Drives


Advantages

Inexpensive and convenient

Large capacity

Several types and formats

Disadvantage

Sequential access (serial)



Connectivity of various tape drives

External

Parallel port with optional pass-through to printer

Internal

IDE ATAPI interface

External or internal

SCSI bus

USB connection, its own proprietary controller card, or floppy drive interface




ZIP and JAZZ Drives

A removable media drive similar to a floppy drive but holds a high capacity of 200 mb.

Both types are similar but made by different companies and use different access architecture.


Jump Drives

Also known as flash drives, keychain drives, etc.