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. |
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