Re: Old Apple2. where to start?

[pubpc1@library.ucla.edu]

spec@vax2.concordia.ca (Mitchell Spector) wrote,
in response to my reply:
>>The loss of DMA is not that big of a deal.  In real world,
>>random read/write situations, it is not very noticeable (except when
>>doing sequential operations like verifying a volume).
>
>    No? My first hardrive setup was an Apple Rev C SCSI board
>connected to an Apple 20SC HD, and to tell you the truth, it
>wasn't much faster than my 3.5 floppy drive (I only kept it
>for about a week or two it was so slow). Granted part of the
>slowness was due to the hardrive mechnism (around 65 ms), the
>controller being non-DMA just made everything _crawl_. I can
>remember trying to load a large MOD file, it took several
>minutes! Loading into GS/OS wasn't much fun either.

There is a fundamental design difference between the High Speed
card and the Rev C card that is not linked just to DMA.  The
High Speed card is a vast improvement over the older card, so
this may be the reason.  Also, the 20SC HD was a slowpoke hard
drive.  :)

On a Quantum ELS 170MB hard disk driven by an Apple II High
Speed SCSI card with the System 6.0.1 driver, I can honestly
say that I have not noticed much speed difference in random
read/write operations.  It is still very fast under GS/OS.
Believe me, if I noticed a big difference, I would say it like
it is (as you've witnessed, I'm a big fan of performance
overkill. :)

>    It was such a pleasure when I got my RamFAST SCSI board and
>connected it up to modern SCSI drive. Quite often I've found it
>as fast as reading/writing to a RAM Disk! DMA makes a huge
>difference, and I wouldn't dream of using anything less.

That's not a fair comparison.  Part of the performance gain is
coming from that modern hard drive being faster than the 20SC HD.
:)  Drives like the slowpoke 20SC did not use internal caching
or any of the performance enhancing features of newer SCSI hard
drives.

>>I used to think 170MB was enough too, but soon my hard disk filled
>>up.  As for the HFS partitions, if you keep them at 96MB or below,
>>they work well.  I've not had any trouble with them.  5 HFS 95MB
>>partitions and a few ProDOS partitions don't seem too much.
>
>    Overflow an HFS partition so you get a "Volume Full" error and
>see what happens. ;) The real problem with HFS isn't just the bugs
>or slow speed, but that fact that there are no HFS utilities for the
>IIgs. Unless you have a Mac handy to connect your hardrive up to,
>your treading on very thin ice using HFS.
>
>Mitchell Spector
>spec@vax2.concordia.ca

That's why you should always back up, Mitchell!

I have another 170MB drive that I back up the data in my three
partitions (two ProDOS and one HFS) to.  It remains off most of
the time, but when I need to back up, I just switch it on and
perform straight volume copies from the Finder.  Since the back
up HD was salvaged from another computer, using it as backup
was the safest bet.  It is a strong temptation to actually erase
the backup volumes and gain double the storage, though.

-Scott G.