Computers (fwd)

From: PG Manney <manney_at_nwohio.com>
Date: Thu Aug 21 16:47:49 1997

> Hi there. I noticed in your collection that you had an IBM PC; I'm
> assuming it's a 5150. Do you have a manual for it that might list the
> jumper and dip switch settings on the motherboard, and if so, could you
> tell me what they are? Thanks.

The 5150 (i.e. the PC) has 2 switchblocks on the motherboard. The one
nearest the power supply Block 2) controls the amount of memory addressed:

Mem Switch number
(KB) 1 2 3 4 5 6 7 8
-------------------------------------
 16 1 1 1 1 1 0 0 0
 32 1 1 1 1 1 0 0 0
 48 1 1 1 1 1 0 0 0
 64 1 1 1 1 1 0 0 0
 96 0 1 1 1 1 0 0 0
128 1 0 1 1 1 0 0 0
160 0 0 1 1 1 0 0 0
192 1 1 0 1 1 0 0 0
224 0 1 0 1 1 0 0 0
256 1 0 0 1 1 0 0 0
288 0 0 0 1 1 0 0 0
320 1 1 1 0 1 0 0 0
352 0 1 1 0 1 0 0 0
384 1 0 1 0 1 0 0 0
416 0 0 1 0 1 0 0 0
448 1 1 0 0 1 0 0 0
480 0 1 0 0 1 0 0 0
512 1 0 0 0 1 0 0 0
544 0 0 0 0 1 0 0 0
576 1 1 1 1 0 0 0 0
608 0 1 1 1 0 0 0 0
640 1 0 1 1 0 0 0 0

0=Off
1=On

Switch block 1 is farther from the power supply

Switch 1 --
        PC -- 0=Boot from Floppy
                1=Do not boot from floppy
        XT -- 0=Normal POST (power On Self Test)
                1=Continuous POST (i.e., won't boot)

Switch 2 -- 0=Math coprocessor installed
                1=Math coprocessor not installed

Switches 3-4 -- Filled memory banks (on motherboard)
        0 0 =All 4 banks
        1 0 = Banks 0, 1, and 2
        0 1 = Banks 0 and 1
        1 1 = Bank 0 only

Switches 5-6 -- Video Adapter
        0 0 = Monochrome (MDA) or Hercules with no onboard BIOS
        0 1 = Color (CGA) 40 chars x 25 lines
        1 0 = CGA 80 chars x 25 lines
        1 1 = Video Adapter w/ onboard BIOS

Note that the PC will support a monochrome adapter at the same time as
another type.

Switches 7-8 -- Floppy Drives
        1 1 = 1 Floppy Drive
        0 1 = 2 FDD
        1 0 = 3 FDD
        0 0 = 4 FDD

Hard drive is taken care of by the adapter card.

Please e-mail me with any other questions.

manney_at_nwohio.com










        
Received on Thu Aug 21 1997 - 16:47:49 BST

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