[TUHS] Unix install & "standalone" package

Clem Cole clemc at ccc.com
Tue Sep 5 05:05:25 AEST 2023

I can not add too much to what happened later, but I think modern users
don't get it why the things like the standalone system were needed back in
the day.  There were a few simple differences thanks to Moore's law, modern
folks really may not grok:

   1. The number of peripherals that needed to be supported was small [each
   firm made only a few for each target system]
   2. The capacity/capabilities of those peripherals are minimal compared
   to today's world
   3. Cheap ROMs, as we know it, were coming on the scene [the EPROM is
   only invented in 1971] One-time programmable and Mask ROMs were around but
   they were expensive and small.

I hope Warren's emailer lets this pass through.

Here is a picture of the original root 'ROM' for the PDP-11 M792-xx board,
which gives you 32 words (64 bytes) of memory.  It used individual diodes
in or out arranged an array to represent individual bits with a diode
present being a '1' and '0' if missing.  As the Gunkies web page suggests,
the board came in two versions - customer programmable which was fully
populated with diodes, and the user removed unneeded diodes to program it.
The other variants were programmed with the designed boot functions -
designated M792-Yx (where 'x' is a capital letter, starting with 'A')

[image: Read_Only_Memory_DEC_M792_Diode_Matrix_ROM_Aceware_Attribution.jpg]

Also,  remember that a $3-5k/drive RK05 is only 2.5Mbytes [4872 512 byte
'sectors' *a.k.a*. disk blocks -- 2 hd/disk * 15 sec/cyl * 203 cyl/disk],
which is why we had separated /bin and /usr/bin and /lib and /usr/lib.
Plus, as Norman points our dynamic linking only comes later, so all of
these are static bound programs (*i.e.,* Sun create /bin and /sbin to
separate those programs).  The whole idea was what was in root was enough
to get the system running in /bin, /lib and /etc and everything else was
one the mounted file system, which often was another RK05.   Many of our V6
and V7 systems ran with 3 RK05 /, /usr /home, and we might have an extra
RK05 for /mnt.  Tape was the standard thing.   DEC tape was cheaper than
9-track, although in my history, we all went for 9-track because it was
more portable to other systems, but often used after-market 9-track
transports that emulated the DEC ones.

Even with the VAX, the front-end runs on an LSI-11 with floppies, so things
like microcode were loaded into the VAX and stored in ROM.   By then, the
RP and RM series had become more normal, and eventually, the RK07 and RL02
replaced the RK05.   But we are not talking about substantial capacity in
the storage systems.   Only ten years later, in the early 1980s, a
Fujisu 'Eagle' is just 470Mbytes and costs 12-15K per drive, plus another
$6-8K for the controller for your Vax [also often after-market from SI or

Sun and Apollo build 'diskless' systems because a 100MB ST-506 style disk
was considered too expensive, and was worried about the entry-level price
of their systems (I famously made a typo describing how those systems
performed BTW with a dyslexic change of the s to c on a whole company email
at Masscomp in the mid-1980s - to Sun's credit, it was the best marketing
ploy ever - people bought diskless and discovered they sucked and then all
added a disk - which cost more $s than the original Masscomp system which
was had one built-in).  But I digress...

Those new workstations did have real ROM chips, unlike the original
PDP-11s, but they were small, maybe 8Kbytes of NS2764, so the ROMs were
tight and only had enough in them to recognize a couple of peripherals.

So to answer more of your question, you build the tools you need that make
sense at the time.   /stand was a simple solution and was small.   For V7
and the original BSD 3 and 4 released, the user needed to read a
distribution media, traditionally a 9-track tape, and set up a local disk.
The number of peripherals was small.

One other thought ... in the case of the PDP-11 and Vaxen, the disks were
often dismountable, like the different RK, RL, RP, and RM series drives.
 We often had more than one system.  So once the system was up and running,
it was not usual to use a different system with better tools to help repair
things if bad stuff occurred.  That is also why we often used 9-track tape,
just because that was even easier to move back and forth.  With the
Wokstrations, the disks were generally sealed.


A  small PS on another note -- I have memories of taking an ST-506 disk
with me to France to work with some engineers in Grenoble and explaining to
the French authorities that they could not open it up to look inside.
 BTW: this pre-internet - imagine what we had to do if we flew to Canada,
which was taxing SW.   Even bringing tapes in and out of Toronto airport
could be treacherous.

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