Is ULTRIX-11 really slow?

[Dave Borman]

Some information on ULTRIX-11, DEC's version of UNIX* for the PDP-11.
The most common question asked is "Why isn't ULTRIX-11 based on 2.9BSD?"

Version 1.0 of ULTRIX-11 was called V7M-11, and was released in August
of 1983. When the work on it was being done, 2.9BSD was not available.
By the time we got a real 2.9BSD tape we were well into development of
2.0, and it would have been foolish for us to put all our changes into
2.9BSD (The time to put in the changes and verify everything would have
meant that 2.0 would still not be out the door).  ULTRIX-11 has followed
a similar history to 2.9BSD, just not at the same pace.  It's not based on
2.9BSD, but it has many 2.9BSD features.  For example: job control, the
terminal driver, the C-shell, overlayed kernels, and overlayed user
processes, to name a few.

We have things that 2.9BSD does not, like error logging (keeps DEC field
service happy!) floating point simulator in the kernel, system verification
programs, new device support, working backup code for all supported
processors.  I can just about guarantee that ULTRIX-11 has the best
MSCP (ra) driver you'll find for the PDP-11.

Sadly enough, some things did not get into 2.0, like stdio line buffering.
This is probably the one missing feature that gives the greatest appearance
of ULTRIX-11 being slow.  This is regretable, but schedules did not allow
enough time.  It will be in the next release, along with many more features
and performance enhancements:  1K file system, System V compatability,
4.2 sockets/TCP/IP (4.2 sockets you say? and running on an 11/23+ with
.5 meg memory?  I did the work, I'll be at Portland USENIX, and will be glad
to answer questions. We should have a pre-release running in the booth).

		-Dave Borman, Digital UNIX Engineering Group
		decvax!borman

* UNIX is a trademark of AT&T Bell Labs
* ULTRIX is a trademark of Digital Equipment Corporation