I've been looking for technical/service docs for
the 4027 and
411x/412x series for a while now.
A recent attempt with Google found this page:
http://www.surplussales.com/Manuals/man_tek.html
That claims to have 402x, 405x and 4081 manuals. The prices are
pretty alarming though.
...but when the fixed disk crashed, it was pretty ugly.
The
machine had a ROM bootloader that allowed booting from a 4051-like
cartrige magtape drive, or disk. Installing the OS took a LONG time
from cartridge tape.
Most vivid GOS memory: The FORTRAN library used the classic
six-letters-or-less "license plate" naming conventions. The name for
the routine to create and open a new file was just one or two letters
different from the routine to format and initialize a volume. You
can see what's coming. "Gee this is taking a long time to
run...maybe it's hung?...better try rebooting...uh oh...". I think
it qualifies as my worst source code typo.
Cheers,
jp