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Re: Ram-Fast vs. Turbo IDE was (Re: RAM-Fast happy and sad)
In article <1993Aug8.061314.5920@ntmtv>, blasjw@ntmtv.com (Joseph Blas) writes:
|> In article <241jl4$cs5@charm.magnus.acs.ohio-state.edu> szatezal@magnus.acs.ohio-state.edu (Shane M Zatezalo) writes:
|> >In article <Aug.7.20.22.14.1993.14271@trident.usacs.rutgers.edu> scraft@trident.usacs.rutgers.edu (Steve Craft) writes:
|> >>HP mechanism in my Pegasus. Works well, but I can't tell if it's faster
|> >>than the Apple HighSpeed SCSI in GS/OS, but it is MUCH faster when I ran
|> >>AppleWorks v3.0.
|> >I'd have to think its a LOT faster. For a while, I had two gs's. One running
|> How does the RAM-Fast card stack up to the Turbo IDE card???
It's about level. The Turbo IDE is a bit faster in sequential read and write,
as far as I have seen (0.7 to 0.8 msecs IDE versus around 1.1 msecs SCSI). Of
course, that also depends on the drive you are using. My old Seagate SCSI
is 1.5 msecs, which is a tad bit slower than IDE drives.
The Turbo IDE is faster when it comes to copying a lot of small files. This
is because the Turbo IDE uses the GS/OS caching mechanism, the RF does not.
CV Tech claims they, after all, had their own cache, BUT: That cache has no
way of knowing that it mustn't purge directory blocks, since it cannot know
what the directory blocks ARE. Only GS/OS knows that. So, when I copy lots
of small files, my HD is beginning a little dance shuttling its head back
and forth. Certainly very healthy exercise, but a bit slow. The Turbo IDE,
in contrast, uses the GS/OS cache which keeps directory information, so
things are less hectic and therefore faster.
Hmm ... the RF does some "dirty" tricks with the RDY line and can therefore
DMA to the upper 4MB of your 8MB memory card. The Turbo IDE cannot, so access
to the upper 4MB is slower than that to the lower 4MB. It's automagic, though,
so it does work w/o disabling DMA ... but you lose some speed if you have the
lower 4MB occupied already. Dunno how much of a concern that is to you ...
I for one don't have 8MB, since RAM prices are so high at the moment. Once they
drop I'll of course get 8 more chips in that CV Tech card (great card, BTW,
if you are shopping around for a mem card, give it due consideration).
Of course, the RF allows you to use Flopticals and Tapes and CD Roms and
Syqyests and what-not. With the Turbo IDE, you are limited to two HDs. But
since that is all a lot of users want anyway, it's a good option.
I just hope that the rumour is true that Sequential takes over the RF. With
some small changes to the drivers (like: GS/OS cache support), it could be
a lot faster in real-life situations.
Yours
Soenke
P.S.: Yes, I know the "author" of the Turbo IDE as a personal friend. No,
I don't get royalties. And I don't think I'm too biased ;)
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