I posted this review of the Corvus Concept about a month ago but since
there have been a couple of requests for information since then and I can't
get mail through to the ARPA net, here it is again. A couple of new items
are included (in particular, the predefined nonstandard Pascal type "string").
I've had my Corvus Concept since August, so here are a few comments.
Here's a list of what's in my system:
Corvus Concept workstation (256Kb memory)
Corvus 5.7Mb hard disk
Corvus 8" disk drive (SSSD)
Okidata ML84 printer
First, the bad news:
The Corvus advertising says that the 8" diskette is 1.0Mb (formated).
It isn't. It stores 256Kb. When I talked to the Corvus marketing people,
it was the first they had heard about it! So much for communication between
engineering and marketing. I settled with Corvus when they agreed to supply
a Mirror interface so I can backup the hard disk on my video cassette recorder.
The 8" drive is capable of double density operation and Corvus says they
will have a DD driver for it in the future.
For the rest of this review, I'll divide things up into Hardware, Software,
and Documentation. I will make a few comments on the printer at the end of
The workstation uses a Motorola MC68000 microprocessor at 8MHz.
It comes with either 256Kb or 512Kb of memory, clock/calendar with
battery backup, 2 RS-232C ports, an Omninet interface (RS-422 1Megabit/
sec.), 4 interface slots (Apple compatible), a 15" 35MHz display monitor.
Sockets are already on board for the second 256Kb of memory. The chips
used are MC6665L20 64K DRAMs.
The battery backup for the Clock/Calendar does not work properly. This
is true not only of my unit but also for the unit purchased by a friend
at the same time. On my unit, the clock appears to run at about half
speed when the power is turned off. On the other unit, the date jumps
about two days when the power is turned off.
There are two serial ports on the Corvus but only one of them can be
used at a time. Bummer!
The display screen may be used in either a horizontal or vertical
orientation. Horizontally this yields 56 lines x 120 chars/line.
Vertically: 72 lines x 90 chars/line.
Display updating uses DMA but with a 50Kb display that means a lot of
bus cycles are being stolen from the processor. Since this is a workstation
and not a multiuser system, however, this isn't too bad and I haven't
noticed any objectionable delays in running programs.
The operating system claims to run up to ten processes. It does not do
time multiplexing however. What it does is let you do is nest program
executions ten deep. Unfortunately, the suspended programs are not swapped
out to disk but remain in memory. So, the deeper you nest the less memory
IO redirection works as it does in the UNIX shell.
There is only one level of directories.
Device drivers can be loaded while the system is running.
Pipes are implemented using temporary files written to a directory called
A very nice character set editor is provided for defining character fonts.
New font files can be loaded while the system is running.
The Pascal compiler supports most of the UCSD extensions. In particular,
UNIT IO and separate compilation (using units). Unfortunately, the compiler
enforces the strict rule of all const definitions first, then all type def-
initions, then all var declarations, etc. This means the use of include
files loses most of its benefits.
The terminal driver supports window management and graphics. Pascal units
are provided to support these.
The predefined type "string" is not only a predefined type but a
reserved keyword as well!! This means you cannot pass variables of
type "string" as procedure parameters since the syntax scan of the
compiler expects a parameter type to be an identifier not a keyword.
I worked around this, by defining:
type pstring = string;
The documentation provided is pretty good as far as it goes. However,
it took some requests to Corvus to get to get system documentation:
description of operating system, LINKER and LIBRARY manuals, ASM68K
manual, description of Pascal Units for accessing system functions.
Some of the documents are missing chapters. For example, the EDWORD
(EDitor/WORDprocessor) manual contains seven chapters but has refer-
ences to chapters up to ten!
No information on memory locations of hardware interfaces, etc., etc.,
The Okidata ML84 printer is great! Some features:
Fast. 200cps (bidirectional, logic-seeking)
Near Letter Quality mode. (unidirectional, two passes per line).
This not only overlaps the dots but puts the little sariphs on the
Underlining, emphasized, super/sub-scripts, graphics.
3 print densities and double width.
Down loadable character fonts. (Doesn't work!)
Electronic VFU and horizontal tabs. (No way to set or recognize
Overall, I am quite pleased with the Concept hardware and rather
disappointed with the software. Function keys and menus are fine when
you are learning a new system but a pain once you know what you are
doing and have nest down thru several windows to get the functions you
want to execute. I am presently working on implementing Software Tools
using their Pascal compiler.
These are a few points that come to mind. If you have any questions
about the system, send me some mail and I will be glad to answer them.