dudek@utai.UUCP (Gregory Dudek) (01/21/86)
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I'm planning on buying a Mac+ as soon as they arrive here (that's
early Feb.) and am interested in information regarding performance
of the Mac+ when used with the HD20, as compared with an old Mac
and a Hyperdrive (or Warp). According to my dealer,
the new ROM code allows a "tremendous performance improvement"
in the HD20 "because on the smart code the drive contains" (?). Is
this just due to cacheing? My impression was the the
Hyperdrive won over external drives by beating
the IO transfer constraints on the external ports. If this is so,
it's not clear how the HD20 can ever make up for it, smarts or no.
Thanks, Greg Dudek.
--
Dept. of Computer Science (vision group) University of Toronto
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CSNET: dudek@Toronto
ARPA: dudek%Toronto@CSNet-Relayolson@harvard.UUCP (Eric Olson) (01/22/86)
My impression of the HD20 is that it cannot be faster than a Hyperdrive. I have no experience with the Warp drive, but I suspect the HD20 is slower than it as well. Here's why: The HD20 + New Roms is changing too many variables at once. Presumably, if you use new Roms you use a new System too. So, the ROMs contain 64K of more stuff that needn't be loaded from disk, an HFS so you needn't build a whole desktop each time you go into Finder, etc. These speed enhancements are not due to the HD20! The HD20, by itself, should be faster than anything going through a serial port, slower than anything directly connected to the processor bus (like Hyperdrive and Warp Drive), and probably slower than anything connected to the (just announced) SCSI port. The current HD20 connects to the external drive port, and therefore has to go through many more protocol conversions than a Hyperdrive/Warpdrive. When the HD20 is available in an SCSI version, it will likely be competitive in terms of speed. Until then, any speed advantage Apple claims is due to the new Roms and System (and HFS), so a Hyperdrive or Warp Drive running the new Roms/System/HFS should still be faster. I'm not sure what software Hyperdrive will run with (or what Roms), but I am sure that they will come out with an HFS compatible Hyperdrive (software) soon. Personally, I am more than happy with the Hyperdrive running the old software, since there IS a fair amount of stuff that I use that won't work right on a HFS machine. -Eric.