info-mac@uw-beaver.UUCP (11/02/84)
From: lewis@harvard.ARPA (Harry Lewis)
I saw a demo this morning of a Mac equipped with a HyperDrive, a 10 MB
Winchester mounted inside the Macintosh case. This is a product
of General Computer, best known as a video game company. For an
estimated $2795, they will take your 128K Mac and return it with
- a 512K memory upgrade
- a 3 1/2 inch, 10 MB winchester mounted inside the cabinet,
somewhere in the rear
- an additional power supply and digital board
- a cooling fan, which vents through the rear right top corner of
the case
- a new 90 day warranty from General Computer. (They'll provide
service after 90 days too, but had no specifics to offer.)
For $2195 they will do the same thing to a Mac that already has 512K
(the drive requires 512K).
The disk interfaces directly to the main system bus, not to a serial
port or the external floppy port. So nothing is removed or restricted --
you still have the internal floppy, the port for a second floppy, and
both serial ports.
Installation is by desoldering the processor chip, mounting an additional
digital board above and parallel to the Mac's board, and reinstalling
the processor on this new board. They claim to achieve a 5 Mbit/sec
transfer rate, though I'm not sure whether that's an empirical or
theoretical figure.
After our disappointment with the Tecmar drive, reported by Dan Winkler
not long ago, I wondered whether they could produce a usable system
built around the Finder with its flat file system. Though we didn't have
a lot of time to beat on it, indications are encouraging. You can
divide the disk into volumes, and can reallocate blocks later to expand,
contract, or garbage collect space. Volumes can be designated as active or
inactive, and only active volumes are searched. In the setup as we saw it,
there were about 6 or 7 volumes, each 500KB, and with a total of about
60 files scattered among them. The volumes show up as separate disk
icons, and when you open one you see how much space is in use in the
volume and how much free space is left on that volume. If you get a file
selection dialog box and keep clicking "Drive", you cycle through all the
active volumes. You still have the Finder's inherent restrictions that a
volume can contain only 128 files and that file names have to be unique,
because they use a standard, unmodified Finder. There is (or will be --
this part of the software we didn't actually see) a desk accessory for
creating, reallocating, and activating/inactivating volumes.
Performance seemed good -- about 7 or 8 seconds to launch Macwrite
and open a small document, and closing and opening documents from within
Macwrite was much faster.
It will be possible (again, this we didn't see but is under development) to
boot directly from the hard disk (if there is a floppy inserted, it boots
from the floppy; if not, it goes to the hard drive). They apparently achieve
this (I think) by extending the ROM (not replacing it, but adding another
ROM in high address space that the startup code always tries to access
but ordinarily finds to be missing). (That was my understanding of how it's
done, but this explanation may not be accurate.)
They are working on various other software utilities and enhancements.
For example, it will be possible to put passwords on individual volumes,
and to encrypt files. There will be a backup utility, which will keep asking
to be fed floppies and spitting them out. It will probably also be possible
to do incremental backups.
With the HyperDrive, the Mac looks identical to an ordinary Mac but
weighs about 5 pounds more. It is claimed to be reasonably shock-resistant
when powered off, since the disk arm locks, but somewhat more delicate
with the power on. Certainly they carried it in and plopped it down like
an ordinary Mac. The fan is variable-speed and thermostatically controlled.
While we were using it (in an ordinary office at ordinary room temperature)
the fan was apparently operating at low speed and was very quiet.
They indicated that if there was enough market interest they would
consider making a 20MB model, since the drive is no larger.
The product is to be launched officially at the Comdex show and will be
available in mid-December. Contact:
Pax Goodson
General Computer Company
215 First Street
Cambridge, MA 02142
(617) 492-5500
Overall, and with the usual cautions I have about systems that are
under development and are viewed for a brief time under somewhat
controlled conditions, I came away from the demo and discussion very
favorably impressed. It's small, fast, intelligently designed from
the standpoint of both software and hardware, and certainly seems
a better option than Davong, Tecmar, or Corvus, based on what I've seen
and others have reported.
- Harry
P.S. Here is a transcript of a draft data sheet Mr. Goodson left with me:
HyperDrive Reference Data Sheet Preliminary
October 11, 1984
Memory: 512K bytes RAM (Model I).
Hard Disk: Internally mounted 10 megabyte
3.5 inch Winchester drive.
Interface to Macintosh: Logic board connected directly to
processor, leaving both serial ports free.
Interface to Operating System: Through Macintosh file system by
volume name or by drive number.
Electrical: Line voltage: 105 to 125 volts AC, RMS.
Frequency: 50/60 Hz.
Power: 110 watts.
Weight: approximately 5 lbs.
Performance: Data Transfer Rate: 5Mbits/second.
Access Time on Disk: 85 milliseconds.
Memory Access Time:
Environment: Temperature: operating: 10 C. to 40 C.
(-50 F. to 104 F.)
storage: -40 C. to 50 C.
(-104 F. to 122 F.)
Humidity, all conditions:
5% to 90% relative humidity.
Altitide: 0 to 4615 M.
(0 to 15,000 feet).