hsc@mtuxo.UUCP (h.cohen) (04/22/86)
The latest BIOS, version 2.01, contains a table of 8 supported disks and their characteristics: 0 10MB 306 cylinders 4 heads < + other parameters> 1 30MB CDC Wren 697 cylinders 5 heads 2 20MB CMI CM6426 640 cylinders 4 heads 3 40MB Tandon 981 cylinders 5 heads 4 40MB Seagate ST4051 977 cylinders 5 heads 5 80MB Miniscribe 8086 1024 cylinders 8 heads 6 67MB Micropolos 1325 1024 cylinders 8 heads 7 20MB Seagate ST225 612 cylinders 4 heads or Miniscribe 3425 Item 7 is the "standard" 20 MB disk currently in use in the PC 6300 PLUS. This table is the same as the one contained in versions 1.04 and 1.06 of the BIOS. The "other parameters" in the table affect performance rather than capacity, so are not listed here. Item 5 should say 67MB instead of 80MB. Hard disk drives C (and, optionally, D) are identified as entries 0-7 in the table by setting one DIP switch on the motherboard and two jumpers on the Western Digital controller board. On the motherboard, there is a package of eight switches labelled "DSW-1." Switch 3 is the most significant bit for drive D, and switch 4 is the most significant bit for drive C. On the HDU controller board, there is a package of eight jumper positions labelled "SW1." _________________________________________________ | (Western Digital HDU controller) | | _________ _______ _______ | | | J1 | | J2 | | J3 | | | --------- ------- ------- | | _______ | | | o o | | | | o o | | | | o o | | | | o o | | | 4| o o | | | 3| o o | | | 2| o o | | | 1| o o | | | ------- | ------------------------------------------------- The next two significant bits are jumper positions 4 and 3 for drive C and 2 and 1 for drive D. In all cases, "OFF" or "Open" is binary "1," and "ON" or "Closed" is binary "0." So, the eight possible settings are: Motherboard Disk Controller Board DSW-1 switch SW1 jumpers 3(D)_or_4(C) 4(C)_or_2(D) 3(C)_or_1(D) setting 0 ON CLOSED CLOSED 1 ON CLOSED OPEN 2 ON OPEN CLOSED 3 ON OPEN OPEN 4 OFF CLOSED CLOSED 5 OFF CLOSED OPEN 6 OFF OPEN CLOSED 7 OFF OPEN OPEN Harvey S. Cohen, AT&T-IS PC6300 PLUS UNIX product mgmt mtuxo!hsc