Re: Alltech Focus Hard Card/8 MB Sirius RAM

[pubpc1@library.ucla.edu]

"Barry Rees" <Barry.Rees@prodigy.net> wrote,
in response to my reply:
>> Barry, it works flawlessly.  There is absolutely no problem accessing
>> all 8MB of memory.
>>
>> -Scott G.
>>
>>
>
>Thanks for the input, Scott. I have also had a couple of emails about the
>Focus/Sirius which were very helpful as well. One thing that came up was a
>mention that in one particular situation AppleWorks wouldn't work with a
>8MB Sirius and the only way this person could get it to work was to create
>a 4 MB RAM disk and run it that way. I am heavily invested in AW v5.1 files
>and having to set up a RAM disk is something that I wouldn't want to have
>to do. Did you (or anyone else) have a problem with AW v5.1 and the Sirius
>8MB card?
>
>Thanks,
>
>Barry
>Barry.Rees@prodigy.net

Yes, I know of that situation.  It happens when you are using the Sirius
(or, apparently, any other 8MB memory expansion) with the Apple II High
Speed SCSI card with DMA turned on.  When the Apple card tries to DMA
to the memory space above the first 4MB on a ROM 1 or the above the
first 5MB on a ROM 3, the access is likely going to fail.  I don't know
about the RamFAST, which has hardware to get around this problem, but
I suspect that in order to be 100% safe, you'd want to disable DMA as
well.  This problem is not limited to AppleWorks, btw.  One way to use
the DMA cards with DMA turned on in an 8MB GS is to set up a 4MB RAM
disk (3MB on a ROM 3), which solves the problem because the computer
will now only DMA to 4MB or 5MB.  Now of course if your intention is
to expand usable memory space for programs, this "solution" is
counterproductive.

The good thing is that if you are going to use the Sirius with a Focus,
this problem does not show up at all.  The Focus is an Enhanced IDE
controller that does not use DMA.  Therefore, it has no conflict with
8MB.  The amazing thing is that the little drive is probably the fastest
non-DMA drive you can get - it is certainly faster than an Apple High
Speed SCSI card with DMA turned off.

-Scott G.