[pups] 2.11BSD disklabel-programm

lothar felten lothar.felten at gmx.net
Sat Jan 26 22:50:49 AEST 2002

about the pdp-11/83:

swapping cpu and memoryboard does work, but
the performance stays the same:
none, because i still don´t have any system
by now. there is a small difference:
the run led stays off all the time, but the
system ODT works fine. i suppose this
is a problem of passing the signals, but this
is only a vague guess.
when i boot the TK50 2.11BSD tape, i can get
the disklabel program loaded.
it asks: Disk?
when i try to access the disks, the system
hangs. when i access rl(0,0) (RL02
disk drive0) the system just hangs, no
response. when i access ra(0,0) (RD54 disk
drive0) i get a "menu": d(isplay) D(efault)
m(odify) w(rite) q(uit)?
i can enter D, then it should write the
defaults to the disk. after this i get:
d(isplay) D(efault) m(odify) w(rite) q(uit)?
i enter d (to see what the program did), and
i get:
(it stops right after tr) i suppose the
program is asking the controller about
drive parameters, and that´s where it fails.
i can wait for hours, i´ll get no
i can use all the menu, except d=display.
i thought that maybe one of the controlles is
broken and causes trouble on the
qbus (maybe the RL02 controller). is there a
way to check all this stuff?
i do have some "winchester" controllers for
PC/ISA, i could check the disks on
a linux pc, no problem, but i don´t want to
overwrite something "digital"-specific
that i could not restore. those RD54-disks
are regular ST506-mfm, right?
maybe i should "downsize" the system to the
basic elements i need to get it running
maybe there really is a bus problem.
i´d try this configuration:
mem - cpu - rqdx3 - tqk50 (top-bottom)
would this be ok?
or, instead of using RD54 disks, should i try
to use the rl02 as "pair" (one swap,
one systemdisk)?
i think step by step checking the hardware is
the only thing i can do to get the
pdp up and running.

have a nice weekend

-- lothar

btw: does anyone know a good book/link about
system-architecture, specially harvard-
architecture ?

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