Re: SCSI-card id? What is it? Help to id.

[dempson@actrix.gen.nz (David Empson)]

Juho Antonio Wahlroos <juanwa@tukki.cc.jyu.fi> wrote:

> Dear apple2-community. Here in the North there is a problem to get
> apple2-related information. Recently I picked up an Apple II SCSI card,
> in original packages *manual was missing, but 5.25 and 3.5 diskette ok.
> (The card seemed not to have been in use as the disks were inside plastic).
> 
> Now, I need to see if I can use it and save many $ without having to order
> enpensive airmail accessories. Firstly it has a 'B' stamp after the s/n
> followed by the year 1986.
> 
> The firmware chip has s/n 341-0437-A and C.Apple'87. Apple Computer has
> manufactured the card and it was made in Singapore.

That is the original Apple SCSI card, with the Revision C firmware (the
last version for that card, and the best version to use).

Hardware limitations (compared to the Apple High-Speed SCSI card):

- No DMA option, hence it is a lot slower.

- No termination on the card.  If you connect two external devices, you
need a pass-through terminator between the card and the first drive, as
well as a terminator after the last drive (a single terminator is
sufficient with one drive connected).

- Unless modified, the card does not provide termination power (same as
the Apple HS SCSI card).

For use on an Apple II+ or IIe, or under ProDOS-8 on a IIgs, the
following limitations should be noted:

-  It supports most SCSI hard drives and a very limited set of CD-ROM
drives (Apple's CD-SC, CD-SC+ and CD-150).

- There is a limit of seven partitions in total over all connected
drives.  You need to use ProDOS-8 2.0 or later to access more than four
partitions.  With earlier versions of ProDOS (back to 1.2), you will
only get access to four partitions if the card is in slot 5, otherwise
you will only see two partitions.

- The firmware does not know about removable devices.  If you intend to
connect something like a ZIP drive or SyQuest, then don't try to switch
disks without rebooting.

If you are using the card on a IIgs under GS/OS, it uses the same
drivers as the Apple HS SCSI card (SCSI.Manager, SCSIHD.Driver, etc.).

> Any ideas? Especially on how to select the id. from a J1, which has 8
> (eight) jumpers and by default the last jumper is closed (i.e. ON).

In its default position (innermost jumper closed), the SCSI ID of the
card is set to 7.  This should not be changed unless you have a very
good reason.

Drives should be set to use SCSI IDs 0 through 6 as appropriate.

> Is it the same electronics as Apple High Speed SCSI card?

Older but similar (except as noted above re missing features).

> Is it capable to handle the same electronics as RamFast?

No.  There is no support for caching, for example.  Its device support
is much more limited.

> Can it handle a SCSI HD as large as 300Mb?

Not under ProDOS-8 (you would never be able to see more than 224MB), but
no problem under GS/OS.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand