Basic PC Technician Facts

Just a place to store some titbits that are often needed when fixing PC’s, especially older PC’s. I’ll try put the older stuff at the bottom. Also great for writing online PC technician test’s because they are often outdated.

Acronym’s

EEPROM – Electrically Erasable Programmable Read Only Memory
DIMM – Dual In-line Memory Module
SO-DIMM – Small Outline Dual In-line Memory Module (for notebooks/laptops)
SIMM – Single In-line Memory Module
SRAM – Static Random Access Memory – Uses transistors and doesn’t need refreshing
DRAM – Dynamic Random Access Memory – Uses capacitors and needs to be refreshed

The advantage of DRAM is its structural simplicity: only one transistor and a capacitor are required per bit, compared to four transistors in SRAM. This allows DRAM to reach very high density. Unlike flash memory, it is volatile memory (cf. non-volatile memory), since it loses its data when the power supply is removed.
EBCDIC – Extended Binary Coded Decimal Interchange Code
ISA – Industry Standard Architecture
SCSI – Small Computer System Interface
FAT – File Allocation Table
MBR – Master Boot Record
BIOS – Built In Operating System
UART – Universal Asynchronous Receiver/Transmitter
VESA – Video Electronics Standards Association
VLSI – Very Large Scale Integration
IRQ – Interrupt ReQuest or Interrupt Request Line
CPU – Central Processing Unit

More available from AcronymDB

COMMON HARDWARE NEEDS

LPT1 – IRQ 7 – Parallel Port DB-25 Female at PC DB-25 Male to Printer

LPT2 – IRQ 5

COM1 3F8-3FF IRQ 4 – Serial Port 9pin Male at PC, 9pin Female to Modem or serial device
COM2 2F8-2FF IRQ 3
COM3 3E8-3EF IRQ 4
COM4 2E8-2EF IRQ 3

STANDARD IRQ ASSIGNMENTS

IRQ PRIORITIES

HIGHEST
0
1
2/9
10
11
12
13
14
15
3
4
5
6
7
8
LOWEST

I/O Addresses

DMA Channels

CAT5 Cabling uses an RJ-45 connector and can transmit upto 1000MB over less than 10 metres, 100MB beyond that to a maximum distance of 100 metres.

RJ-45 – Registered Jack 45 – primarily ethernet cabling CAT5, also used for??? Max cable length 1000T base is 100 metres.

3.5″ 1.44MB Stiffy Disk (96tpi)
RISC is better than CISC at number crunching – True although less and less so

SCSI Hard drive connector has 50pins (HD50)

BAUD Rate -the number of distinct symbol changes (signaling events) made to the transmission medium per second in a digitally modulated signal or a line code. The baud rate is related to but should not be confused with gross bit rate expressed in bit/s.

How does disk fragmentation occur?

IDE cable 40 pins

Serial ports rely on a special controller chip, the Universal Asynchronous Receiver/Transmitter (UART), to function properly. The UART chip takes the parallel output of the computer’s system bus and transforms it into serial form for transmission through the serial port. In order to function faster, most UART chips have a built-in buffer of anywhere from 16 to 64 kilobytes. This buffer allows the chip to cache data coming in from the system bus while it is processing data going out to the serial port. While most standard serial ports have a maximum transfer rate of 115 Kbps (kilobits per second), high speed serial ports, such as Enhanced Serial Port (ESP) and Super Enhanced Serial Port (Super ESP), can reach data transfer rates of 460 Kbps.vi