Apple DOS Compatibility Card
| Apple DOS Compatibility Card | |
|---|---|
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| The Centris and Quadra 610 card with its 25 MHz 486SX (photo: Yuri Litvinenko, CC BY 2.0) | |
| Manufacturer | Apple Computer |
| Type | PC compatibility card (Intel 486 on a processor-direct slot card) |
| Release date | 1994 |
| Interface | Processor-direct slot |
| Compatible | Centris 610 and Quadra 610 (M2153LL/A); Power Macintosh 6100/60, 6100/66 and Performa 6100 series (M3581LL/A); built into the LC 630 and Performa 640 DOS Compatible |
| Model | M2153LL/A, M3581LL/A |
| Part number | 661-1017 (Quadra 610 card) |
The Apple DOS Compatibility Card is Apple's name for the cards that put an Intel 486 PC inside a Macintosh, so that MS-DOS and Windows programs run on the 486 while the Mac OS keeps running on the Macintosh processor. The two processors work independently; the PC uses the Macintosh's display, disks, keyboard, mouse, ports and network, and the user switches between the two environments with a key or runs a second display.[1][2] There were three versions, each tied to particular Macintosh models: a 486SX card for the Centris and Quadra 610, a 486DX2 card for the Power Macintosh 6100, and the 486DX2 card built into the LC 630 and Performa 640 DOS Compatible.[3][4] Apple's later PC Compatibility Cards are a separate line.[5]
| Card | Processor | Card RAM | DOS video | Hosts |
|---|---|---|---|---|
| DOS Compatibility Card, M2153LL/A | Intel 486SX, 25 MHz | One 72-pin SIMM, up to 32 MB | 512K | Centris 610, Quadra 610; built into the Quadra 610 DOS Compatible |
| DOS Compatibility Card for Power Macintosh, M3581LL/A | Intel 486DX2, 66 MHz | One 72-pin SIMM, up to 32 MB | 512K | Power Macintosh 6100 (not AV models), Performa 6100 series; built into the Power Macintosh 6100 DOS Compatible |
| LC 630 DOS card | Intel 486DX2, 66 MHz | 4 MB SIMM fitted, one 72-pin socket, up to 32 MB | 512K | Built into the Macintosh LC 630 DOS Compatible and Performa 640 DOS Compatible |
From Apple's specification sheets.[6][7][2][4][3] The card occupies the processor-direct slot in each machine, so nothing else can use that slot.[8]
Centris and Quadra 610 card
[edit | edit source].jpg)
The first card is a 7-inch board for the 68040 processor-direct slot of the Centris 610 and Quadra 610, drawing at most 10 W from +5 V.[6] Apple also sold the Quadra 610 with the card already fitted as the Quadra 610 DOS Compatible.[1] The 486SX is socketed. A 486DX of the same speed fits after minor changes to the board, but Apple did not support it.[5] The DOS side gets VGA modes 0 to 7 and 13h, SVGA at 640 × 480 and 800 × 600 (the latter on the 16-inch display only), and EGA, CGA and MDA. The Windows driver disks install a 1024 × 768 driver, but with 512K of video RAM the card cannot go above 800 × 600.[6][5] The Macintosh serial ports appear to DOS as two 16450-type serial ports, the printer port as a parallel port, and the ADB keyboard and mouse as an AT keyboard and PS/2 mouse; PC sound plays through the Macintosh speaker.[6] Apple's service module is 661-1017; return it without its SIMM.[9]
Power Macintosh 6100 card
[edit | edit source]The DOS Compatibility Card for Power Macintosh carries a 66 MHz 486DX2, adds SoundBlaster 16 output on a small sound card, and came with MS-DOS 6.22 and Windows 3.1. An ODI driver lets DOS and Windows use NetWare IPX and TCP/IP over the built-in Ethernet.[2] It fits the 6100/60, 6100/66 and Performa 6100 series, but not the 6100/60AV, whose AV card already occupies the slot.[3][10] Apple did not test it in 68040 machines: a Quadra fitted with it froze at start-up under System 7.5 with PowerTalk.[11]
The upgrade kit holds the card in a bracket adapter, a monitor cable with four connectors, a hard drive power extension cable, a monitor cable adapter, a CD-ROM audio cable and two thumbscrews. With a CD-ROM drive, the drive's audio cable goes to the card's CD In connector and the kit's cable runs from the card's Sound Out connector to the logic board.[10] The full procedure is on the Power Macintosh 6100 DOS Compatible page.
Jumper J10 on the card is mismarked. It must sit in the "SX" position, over the two right-most pins. Apple traces intermittent stack overflow errors in DOS or Windows, and a screen that sometimes stays blank when the card starts, to this jumper.[10] Remove the sound card before returning a card to Apple.[10]
LC 630 and Performa 640 card
[edit | edit source]The LC 630 DOS Compatible and Performa 640 DOS Compatible have a 66 MHz 486DX2 card with a 4 MB SIMM, a SoundBlaster 16 compatible sound board and a DB-15 joystick port. Its 512K frame buffer gives 8-bit colour at 640 × 480 and 4-bit colour at 800 × 600.[4] The Macintosh LC 630 DOS Compatible page covers the boards in these machines.
Memory
[edit | edit source]The PC side can use shared memory taken from the Macintosh logic board or local memory on the card's own SIMM, but not both. Shared memory is set in the PC Setup control panel, and at least 4 MB must stay with the Mac OS; a 16 MB SIMM in a Quadra 610 allows 12 MB for the PC. Once a SIMM is fitted to the card, the PC uses only that, and the Macintosh cannot use it. Virtual memory does not count: the card sees only physical RAM. Card SIMMs must be 72-pin, 80 ns or faster.[12][5][2]
Display and game port cable
[edit | edit source]A special cable joins the card to the Macintosh video port, the display and the PC game port.[13]
| Signal | Card pin | Mac video pin | Monitor pin | Game port pin |
|---|---|---|---|---|
| SW 1A | 1 | 2 | ||
| R AX | 2 | 3 | ||
| R AY | 3 | 6 | ||
| Blue | 4 | 9 | 9 | |
| Green | 5 | 5 | 5 | |
| Mac CSYNC | 6 | 3 | ||
| Cable detect | 7 | 14 | ||
| HSYNC out | 8 | 15 | ||
| Sense 0 | 9 | 4 | 4 | |
| +5 V | 10 | 1, 8, 9, 15 | ||
| R BX | 11 | 11 | ||
| R BY | 12 | 13 | ||
| SW 2A | 13 | 7 | ||
| Blue ground | 14 | 13 | 13 | |
| Green ground | 15 | 6 | 6 | |
| Mac HSYNC | 16 | 15 | ||
| VSYNC out | 17 | 12 | ||
| Sense 1 | 18 | 7 | 7 | |
| SW 1B | 19 | 10 | ||
| Ground | 20 | 11 | 11, 14 | 4, 5, 12 |
| SW 2B | 21 | 14 | ||
| Red | 22 | 2 | 2 | |
| Red ground | 23 | 1 | 1 | |
| Mac VSYNC | 24 | 12 | ||
| CSYNC out | 25 | 3 | ||
| Sense 2 | 26 | 10 | 10 |
Troubleshooting
[edit | edit source]| Symptom | Probable cause | Action |
|---|---|---|
| Stack overflow errors in DOS or Windows, or a blank screen when the PC starts (6100 card) | Jumper J10 in the wrong position; the marking is wrong | Remove the card and set J10 to "SX", over the two right-most pins[10] |
| Wavy horizontal lines or flicker in DOS on a single Apple 14-inch Macintosh Color Display | Interference on the horizontal sync line | Install PC Setup 1.2 (System Update 3.0) and select "Fade Screens"[14] |
| Checkerboard DOS screen in a very cold room | Temperature near freezing | Let the machine warm up; the pattern clears[15] |
| A DOS program shows black and white on a colour display | The program misdetects the display | Use the program's command-line video switch[15] |
| Cannot give the PC all the memory | 4 MB must stay with the Mac OS; shared memory stops once the card has a SIMM | Add RAM to the logic board, or fit a SIMM to the card[12] |
| DOS date and time reset after a restart | The card has no clock and reads the Macintosh clock at start-up | Normal; set the Macintosh clock[5] |
| Quadra freezes at start-up with the Power Macintosh card fitted | Unsupported in 68040 machines | Use the card in a 6100; turning off "Auto-start PC" may help[11] |
Related pages
[edit | edit source]- Apple PC Compatibility Card
- Power Macintosh 6100 DOS Compatible
- Macintosh Quadra 610 DOS Compatible
- Macintosh LC 630 DOS Compatible
- Apple IIe Card
References
[edit | edit source]- ↑ 1.0 1.1 Apple Computer, "Quadra 610, DOS Compatible: Description (2/94)", Tech Info Library article 13884, revised 17 February 1994, APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: the 25 MHz 486SX working independently of the 68LC040; 512K of RAM for DOS video; support for one or two displays and the displays usable in each environment; the external PC game port; the card offered as an upgrade for the Centris 610 and Quadra 610; order numbers M2322LL/A and M2153LL/A.
- ↑ 2.0 2.1 2.2 2.3 Apple Computer, "Pwr Macintosh DOS Compatibility Card: Specifications (6/95)", Tech Info Library article 16756, revised 12 June 1995, APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: the 66 MHz 486DX2 with a 32-bit data bus; one 72-pin SIMM slot for up to 32 MB of 80 ns local RAM, or shared memory set in the PC Setup control panel; 512K for DOS video; SoundBlaster 16 output; MS-DOS 6.22 and Windows 3.1 included; ODI driver for NetWare IPX and TCP/IP over the built-in Ethernet; PC game port; supported displays; no dealer installation needed; order numbers M3581LL/A and M3972LL/A.
- ↑ 3.0 3.1 3.2 Apple Computer, "DOS Compatibility Card: Macintosh Models Supported (6/95)", Tech Info Library article 14938 (TA31387), APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: M2153LL/A only for the Quadra 610 and Centris 610; M3581LL/A only for the Power Macintosh 6100/60 and 6100/66 and Performa 6100 series, not the 6100 AV models.
- ↑ 4.0 4.1 4.2 Apple Computer, "Macintosh LC 630 DOS Compatible: Specifications (6/95)", Tech Info Library article 17846, APPLE_TIL_ARTICLES collection, file TIL17065_to_TIL60496.pdf. Source for: the PC side's 66 MHz 486DX2; 4 MB SIMM standard, one 72-pin socket to 32 MB at 80 ns; SoundBlaster 16 compatible output; DB-15 joystick port; serial and parallel emulation; 512K video frame buffer with 8-bit colour at 640 × 480 and 4-bit at 800 × 600; DOS 6.22 and Windows 3.1.
- ↑ 5.0 5.1 5.2 5.3 5.4 Apple Computer, "DOS (486) Compat Card: Frequently Asked Questions (3/97)", Tech Info Library article 15148 (TA31544), APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: the socketed 486SX, with a 486DX of the same speed fitting only after minor board changes and not supported by Apple; no clock of its own on the card; the unused connector being a subset of the ISA bus; 512K of video RAM and a maximum of 800 × 600 despite the 1024 × 768 Windows driver; 80 ns SIMMs; virtual memory not usable by the card; DoubleSpace not recommended.
- ↑ 6.0 6.1 6.2 6.3 Apple Computer, "Macintosh DOS Compatibility Card: Specifications (3/94)", Tech Info Library article 14781, in the archive.org collection APPLE_TIL_ARTICLES (retrieved 2026-10-04), file TIL09433_to_TIL17062.pdf. Source for: the 7-inch card for the 68040 processor-direct slot of the Centris 610 and Quadra 610; +5 V, 10 W maximum; one 72-pin SIMM to 32 MB; one 32-bit DMA channel and shared memory; VGA modes 0-7 and 13h, SVGA 640 × 480 and 800 × 600 (16-inch only), EGA, CGA and MDA; PC sound through the Macintosh speaker; serial, parallel, keyboard and mouse emulation; order number M2153LL/A.
- ↑ Apple Computer, "Macintosh Quadra 610 DOS Compatible: Specifications (1/95)", Tech Info Library article 14670, revised 13 January 1995, APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: the 486SX at 25 MHz with a 32-bit data bus; the card's single 72-pin SIMM slot for up to 32 MB of 80 ns RAM; DOS access to either shared memory on the logic board or local memory on the card.
- ↑ Apple Computer, "DOS Compatibility Card: List of Available Expansion Slots (6/95)", Tech Info Library article 17863, APPLE_TIL_ARTICLES collection, file TIL17065_to_TIL60496.pdf. Source for: the processor-direct slot taken by the card in the Quadra 610, Power Macintosh 6100 and LC 630 DOS Compatible; the RAM, cache, communications and video slots still free.
- ↑ Apple Computer, Module Identification, part number 072-8124, June 1994, hosted as File:Apple Service Module Identification Manual (June 1994).pdf, p. 4.7.1 (PDF page 267): "Macintosh Quadra 610 DOS Compatibility Card", Apple P/N 661-1017; return the card without DRAM SIMMs.
- ↑ 10.0 10.1 10.2 10.3 10.4 Apple Computer, Power Macintosh 6100 Series Service Source, hosted as File:Powermac_6100_series.pdf (see Power Macintosh 6100/ WS 6150 Service Source). Troubleshooting, Symptom Charts/Miscellaneous (continued) p. 16: stack overflow errors and blank screens cured by setting jumper J10 to "SX"; Take Apart, DOS Compatibility Card pp. 15-22: removal, the sound card to be removed before return, J10 mismarked; Upgrades, DOS Compatibility Upgrade pp. 13-26: kit contents, the 6100/60AV unable to take the card, installation with and without a CD-ROM drive.
- ↑ 11.0 11.1 Apple Computer, "Pwr Mac DOS Compatibility Card: Not For 68040 Computers (2/95)", Tech Info Library article 17286, APPLE_TIL_ARTICLES collection, file TIL17065_to_TIL60496.pdf. Source for: a Quadra freezing at start-up with System 7.5 and PowerTalk when fitted with M3581LL/A; the card untested and unsupported on 68040 machines; turning off "Auto-start PC" as a possible workaround.
- ↑ 12.0 12.1 Apple Computer, "DOS Compatibility Card: How Memory Is Allocated (9/95)", Tech Info Library article 15095 (TA31509), APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: memory allocated in the PC Setup control panel from the logic board; at least 4 MB left to the Mac OS; a SIMM on the card ending the use of shared memory, and card RAM not usable by the Macintosh.
- ↑ Apple Computer, "DOS Compatibility Card: Speciality Cable Pinouts (8/94)", Tech Info Library article 15308 (TA31667), APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: the pinout of the cable joining the card to the Macintosh video port, the display and the game port.
- ↑ Apple Computer, "DOS Compatible Card: Video Noise in PC Environment (5/96)", Tech Info Library article 15268 (TA31639), APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: wavy horizontal lines in DOS on a single Apple 14-inch Macintosh Color Display, caused by interference on the horizontal sync line; the fix in PC Setup 1.2 from System Update 3.0 with "Fade Screens" selected.
- ↑ 15.0 15.1 Apple Computer, "DOS Compatibility Card: Cold Creates Checkerboard Pattern (5/94)" (article 15457) and "DOS Compatibility Card: Black & White Video In DOS Mode (5/94)" (article 15442), Tech Info Library, APPLE_TIL_ARTICLES collection, file TIL09433_to_TIL17062.pdf. Source for: a checkerboard DOS screen only near freezing, clearing as the machine warms; some DOS programs showing black and white because they misdetect the display, cured by the program's own video switch.