Re: Focus HD -> CF Questions

["mdj" <mdj.mdj@gmail.com>]

On Mar 7, 6:35 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> aiiad...@gmail.com wrote:
> > On Mar 6, 7:55 am, "John" <zzzj...@yahoo.com> wrote:
>
> >>Problem - the CF disk will not warm boot with a Control-OA-Reset I also
> >>have this problem with another Focus card & HD which I formatted.
>
> > I had this problem with my Focus (before it killed itself)...
>
> > Pressing control-reset sends a reset to the card...  during reset, the
> > hard drive power is removed.  When you release the keys, the HD goes
> > through its startup procedure (spin up, move the head)...  This
> > startup
> > procedure takes too long on ?some? HD's, and the card is already
> > trying
> > to boot the drive even though the drive isn't ready to go yet.  When
> > the
> > HD is done with its startup procedure, the computer is locked up ?
> > looking
> > at the focus card?...  Solution:  control reset to get to a prompt.
> > if you get
> > to ] prompt, type PR# (whatever slot the focus is in)... if you get to
> > the * prompt,
> > type CX00G, where X = slot you have your focus in.
>
> Seems like stopping the reset from powering down the HD is the right
> answer (what was the designer thinking!).  But I find it hard to believe
> that a CF card takes "too long" to power up--mere milliseconds should be
> plenty.
>
> >>Speed - the CF card seems about as fast as the HD. It's an old 8 meg
> >>card from a Camera. I wonder if a faster CF card would speed things up
> >>more, or is the 1MHz //e the bottleneck?
>
> > ??  less than 10 seconds boot is too slow for you ??  I imagine a HD
> > would be
> > faster than a CF card...

Depends on what you're booting. My IIe warmboots into ProSel in < 3
seconds, and about double that if the accelerator is disabled.

> > I think all you can do is get better media device with a faster seek
> > time...
>
> It can't be seek time--a CF card doesn't have any to speak of.
>
> It's the byte-by-byte programmed data movement on a 1MHz machine that
> is the limiter, and I doubt that there are any plans for a DMA version
> that could, in principle, sustain a 1MB/sec maximum bandwidth.

On the IIe you're also limited by the single block 'funnel' IO model
of ProDOS which probably impacts throughput just as much, since
there's never any multiblock transfers.

> In fact, those of us with accelerated //e's would have to turn off the
> DMA it it had it.  ;-(

It's debatable that there's any practical difference between DMA on a
non-accelerated IIe vs. non-DMA on an accelerated IIe. At least on my
setup (Transwarp I, Apple SCSI) using the accelerator in conjunction
with a Rev C SCSI card is actually as fast or faster than a high-speed
SCSI without the accelerator.

It'd be nice to have the best of both worlds, but I'm unconvinced that
accelerated PIO would end up being percievably better than accelerated
DMA anyway, and unfortunately there's no way to test it, unless
somebody has one of the fabled Transwarp III's lying around.

On the IIgs the game is different, since GS/OS is considerably
smarter.

Matt