A2 SCSI Cards - wiki.apple2.org

A2 SCSI Cards

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Apple Rev C SCSI Interface Card, Part # 820-0193-A Any Apple II With 64K & ProDOS 8. Same as CMS SCSI

Apple II High Speed SCSI Interface Card, Part #A02200LL/A An Enhanced Apple //e with 128K or an Apple IIgs

RAMFast SCSI Card from CV Technologies. An Enhanced Apple //e with 128K or an Apple IIgs

SCSI Interface Card Specifications

The CMS SCSI II Interface Card

Requires: 64K II+, //e, IIgs, Laser 128 / Compatibles.

Data Transfer Rate: Approx 64-128K / Sec

The CMS Card does not support the same standard Apple Partition Map like most other cards do.

There are 3 ROM Revisions available for the CMS Card, the first, and most common has a date of 11/09/87. The intermediate ROM is dated 03/01/89 and is similar in restrictions as the original.

To use a hard disk with this card, it requires that the user set a series of jumpers to thier needs and it will only support up to 64 Meg. (2 32 Meg Partitions). To access a larger drive requires the addition of another SCSI card to the system, with itself set to a different ID.

That means that of you had a 120 Meg drive and wanted four partitions- you would need to use TWO SCSI cards with a cable running between them on the outside of the computer, or custom crimped ribbon cables inside.

The third and final ROM being dated 4/1/90 does NOT have the same limitations as the older two, it can utilize the card WITHOUT setting jumpers for sizes. The jumpers are set in a certain way for most users and left alone. The ROM automatically partitions in 32 meg increments until the end of the drive is reached. There is an upper limit on the number of partitions. It is not as many as the Apple Inside Mac V Partitioning Scheme allows. This is how most other SCSI cards work.

CMS SCSI Networking

Now, here is a fun tidbit;

Have one hard drive and two computers? Want to use it? Put a SCSI card in each and hook each computer to one of the connectors. File locking is all your own problem. But you can do it. Multiline BBS? Great simple solution.

The CMS SCSI Card is not recommended for use in the Apple IIgs at all.

The Apple SCSI Card

Requires: 64K II+, //e, IIgs, Laser 128 / Compatibles.

Data Transfer Rate: 128-256K / Sec

This card is made by Apple Computer and was released as a Rev. B and later upgraded to Rev. C. No hardware changes were done, just firmware. It was superseded by the High Speed SCSI Card.

The Rev. B card has 342-0112C on it's ROM and the Rev. C is labeled 342-0437B. In the Rev. B configuration this card supports four partitions in placed in Slot 5 and two partitions if placed in Slot 7. Additionally, Rev. B does NOT support the Inside Mac V Partitioning Scheme.

The Rev. B will also boot a drive that was formatted with a CMS SCSI card and the first partition only, will be accessible.

The Rev. C, with ProDOS 8 will access more than 2 partitions. ProDOS 8 will automatically map the partitions, two per slot, in any 'position' not occupied by another storage device already. If you have a 5.25" controller installed, that will pre-empt that slot position regardless if you have one or two drives attached. A 3.5" controller will allow one HD partition to be mapped as Drive #2 if you have only one 3.5" drive attached. Any other slots, empty or occupied by NON block/storage devices will have a partition mapped to them except Slot 3, which will only have one, unless you have disabled the /RAM volume. In an Apple IIgs, GS/OS can recognize up to 40 partitions of 32 Meg each, thus allowing the use of a much larger drive. The Apple Inside Mac V Partitioning Scheme is the method used here, meaning devices used with this SCSI card can be moved between an Apple High Speed SCSI card, the RAMFast SCSI card* and the Macintosh**

The Apple High Speed SCSI Card

Requires: Enhanced Apple //e 128K, Apple IIgs

Data Transfer Rate: IIgs 1Meg / Sec - //e 512K / Sec

This card has all the same characteristics of the Apple II Rev C. Card, and is downwardly software compatible with it. That is where the difference stops, it is a totally new, redesigned card. It offers 1 Megabyte a second data transfer rate* (512K on an Apple //e) and is DMA, (Direct Memory Access) compatible.


Requires: Enhanced Apple //e 128K, Apple IIgs

Data Transfer Rate: 1 Meg / Sec

Cache Size: 256K or 1024K

This card, is compatible with the Apple High Speed SCSI card, capability wise, it is not compatible with software for the Apple SCSI Cards. It offers all the same hardware specs as the Apple High Speed SCSI card, with the addition of hardware caching, it has 256K or 1024K of cache-ahead buffering, thus making it the FASTEST SCSI CARD available for the Apple II.

  • *The RAMFast supports Inside Mac V Partitioning however it is limited to 12 partitions only.
  • **Using SCSI hard drives from an Apple II on a Macintosh requires some method of support for the ProDOS file system. There is an extension for ProDOS support for Mac OS 7.5 through OS 9.2. Be aware the ANY files written directly to a locally attached ProDOS volume from Mac OS WILL HAVE RESOURCE FORKS APPENDED and will NOT work with ProDOS 8 any longer, until the resource forks are stripped.

Cirtech SCSI Interface Card

Requires: Apple ][ (64K), ][+ (64K), //e or IIgs

Data Transfer Rate: SLOW: 47kbyte/sec, FAST: 100kbyte/sec

Cache Size: none

This card supports up to 4x 32MB partitions under ProDOS 8 & 16, 4x 8GB under CP/M Plus, 2x 16MB under Pascal 1.3, 2x 400KB under DOS 3.3 and 2x 1.5MB under Microsoft CP/M.

Unlike SLOW mode, FAST mode has SmartPort ID bytes meaning that it will not auto-boot on Apple ][, ][+ and un-enhanced IIe systems.

There is an optional Multi-User System available allowing a SCSI drive to be shared between up to 7 Apple computers.

Cirtech InSyder

Requires: 80 column Apple //e or IIgs

Data Transfer Rate: SLOW: 47kbyte/sec, FAST: 100kbyte/sec

Cache Size: none

Similar to the earlier Cirtech SCSI Interface Card, the InSyder supports an optional internal 2.5" SCSI drive, an external printer port adapter and the Mult-User software is standard.

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