Specifications

Computer Architecture and Maintenance (G-Scheme-2014)
Additional - Information
Q.State Feature of XT mother Board
Ans. The following list shows the highlights of these new models:
 Enhanced keyboard standard on Models 268, 278, and 089; 101 keys, and no
status LEDs
 (XT interface cannot drive LEDs)
 Standard PC XT keyboard on Models 267, 277, and 088
 More disk capacity (20MB)
 Standard 5 1/4-inch, half-height, 360KB floppy drive
 Available 3 1/2-inch, half-height, 720KB floppy drive
 Capacity for four half-height storage devices within the system unit
 Capacity to expand to 640KB memory on system board without using expansion
slots
System Architecture
• Microprocessor 8088
• Clock speed 4.77MHz
• Bus type ISA (Industry Standard Architecture)
• Bus width 8-bit
• Interrupt levels 8 (6 usable)
• Type Edge-triggered
• Shareable No
• DMA channels 4 (3 usable)
• Bus masters supported No
• Upgradeable processor complex No
Memory Architechture
• Standard on system board 256KB or 640KB
• Maximum on system board 256KB or 640KB
• Maximum total memory 640KB
• Memory speed (ns) and type 200ns Dynamic RAM chips
• System board memory-socket type 16-pin DIP
• Number of memory-module sockets 36 (4 banks of 9)
• Memory used on system board 36 64KB ×1-bit DRAM chips in 4 banks of 9, or 2
banks of 9
• 256KB ×1-bit and 2 banks of 9 64KB ×1-bit chips
• Memory cache controller No
Prepared By – Prof. Manoj.kavedia (9860174297 – 9324258878 ) (www.kavediasir.yolasite.com)
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