[net.micro] Micro Vax I

garret@uw-june (Garret F. Swart) (11/29/83)

I haven't read anything about the Micro Vax I just announced by Digital.  They
gave their second product demo here last week so I thought I would throw in
some information about it onto the net.

The Micro Vax I is a LSI implementation of the Micro Vax architecture, a subset
of the full Vax architecture.  The major missing instructions are:
   Decimal arithmetic, edit instruction, odd floating point formats, PDP-11
   emulation mode.

The design is split into three parts, a micro programmed CPU with an LSI data
path chip (containing a barrel shifter), a micro programmed Memory Manager
with a cache, look aside buffer etc. for a full implementation of the VAX 
virtual memory, and a Q-bus controller.  It fits on two quarter size boards
and fits in the LSI-11 case and interfaces to all its periferals.

It is currently running VMS and a limping version of Unix 4.1BSD.  They are
currently working on tuning the Unix version.  As was expected they have 
unbundled the software from the machine and allow one to buy what one wants
as needed.  The entire software set for this machine is expected to sell for
$4000.

By the way, the machine with 2Megs of main memory and a 25Meg hard disk and
controllers for 5 terminals is expected to sell for $10000, sans software.
Ethernet boards and everything else made for the LSI-11 will work on the
machine.  They are currently working on a bitmap terminal that will plug
right onto the Q-Bus as part of their "Vax Station" concept.

They are not giving out bench mark data, but they suggest that the machine
is as fast as a 730 for most instructions, and twice as fast for floating
point.  The design team contains some of the brightest people at digital
who are working near Seattle at DEC-West.  The design seems to be as risk
free as is possible.  All the control logic is in SSI, and MSI and in
17 PLA's, with only the most stable part of the design, the data path, in
LSI.  The data path chip was, by the way, designed correctly the first time
with help from Carver Mead.

The bottle neck on the machine is the 22 bit Q-bus which was used so that
the Micro Vax I could
be sold as a complete system as soon as possible.
DEC West is still full of bright ideas and I don't think we have long to wait
for an improved Micro Vax II.

Garret Swart
University of Washington
(I have no relationship with DEC)

garret@uw-june (Garret F. Swart) (11/29/83)

From garret@uw-june (Garret F. Swart) Wed Dec 31 16:00:00 1969
Relay-Version: version B 2.10 5/3/83; site uw-june
Posting-Version: version B 2.10 5/3/83; site uw-june
Path: uw-june!garret
From: garret@uw-june (Garret F. Swart)
Newsgroups: net.micro
Subject: Micro Vax I
Message-ID: <775@uw-june>
Date: Tue, 29-Nov-83 11:17:30 PST
Article-I.D.: uw-june.775
Posted: Tue Nov 29 11:17:30 1983
Date-Received: Tue, 29-Nov-83 11:17:30 PST
Organization: U. Washington, Computer Sci
Lines: 45

I haven't read anything about the Micro Vax I just announced by Digital.  They
gave their second product demo here last week so I thought I would throw in
some information about it onto the net.

The Micro Vax I is a LSI implementation of the Micro Vax architecture, a subset
of the full Vax architecture.  The major missing instructions are:
   Decimal arithmetic, edit instruction, odd floating point formats, PDP-11
   emulation mode.

The design is split into three parts, a micro programmed CPU with an LSI data
path chip (containing a barrel shifter), a micro programmed Memory Manager
with a cache, look aside buffer etc. for a full implementation of the VAX 
virtual memory, and a Q-bus controller.  It fits on two quarter size boards
and fits in the LSI-11 case and interfaces to all its peripherals.

It is currently running VMS and a limping version of Unix 4.1BSD.  They are
currently working on tuning the Unix version.  As was expected they have 
unbundled the software from the machine and allow one to buy what one wants
as needed.  The entire software set for this machine is expected to sell for
$4000.

By the way, the machine with 2Megs of main memory and a 25Meg hard disk and
controllers for 5 terminals is expected to sell for $10000, sans software.
Ethernet boards and everything else made for the LSI-11 will work on the
machine.  They are currently working on a bitmap terminal that will plug
right onto the Q-Bus as part of their "Vax Station" concept.

They are not giving out bench mark data, but they suggest that the machine
is as fast as a 730 for most instructions, and twice as fast for floating
point.  The design team contains some of the brightest people at digital
who are working near Seattle at DEC-West.  The design seems to be as risk
free as is possible.  All the control logic is in SSI, and MSI and in
17 PLA's, with only the most stable part of the design, the data path, in
LSI.  The data path chip was, by the way, designed correctly the first time
with help from Carver Mead.

The bottle neck on the machine is the 22 bit Q-bus which was used so that
the Micro Vax I could
be sold as a complete system as soon as possible.
DEC West is still full of bright ideas and I don't think we have long to wait
for an improved Micro Vax II.

Garret Swart
University of Washington
(I have no relationship with DEC)

minow@decvax.UUCP (Martin Minow) (12/01/83)

Garret Swart's interesting article on the Micro Vax contained one
statement that might be confusing to readers unfamiliar with the
LSI-11 Q-bus -- that it is a "22-bit bus"

The 22 bits refers to the number of address bits that the bus
supports.  The bus may be a bottleneck because address and
data are carried on the same signal lines, rather than on
separate lines as on the Unibus.   (This is from memory --
so don't blame Dec if I'm wrong.)

The Q-bus and Q-bus periferals are much less expensive to manufacture
than the Unibus, a savings that is reflected in the price of the
product.

Martin Minow
decvax!minow