My boss made me format our disk and reinstall
linux and d3 recently,
and I cut a pseudo-floppy to go with our file-save tape,
but ABSDUMP is a bit tricky to use, so I thought I'd
note the steps here. This will make an uncompressed
file, so use a line like

tape /v/pickbu1 500 f lx # comment area
{That's lowercase for TAPE /V/PICKBU1 500 F LX # etc}

in your /usr/lib/pick/pick0 file for this chore.

Log in to DM
! > /v/pickbu1
{that creates pickbu1, or shortens it if already existed}
SET-DEVICE
....now find the row-number that has /v/pickbu1
and type that number in please.
Observe please that it attached at size 500 bytes.
This is not good for our purpose, so do
T-ATT 512
Note this next command has two commas and only 2 spaces!
ABSDUMP DM,ABS, (LL
T-REW
T-DET
Expect a pickbu1 file roughly a couple of megabytes long.
Notice the spelling of ABSDUMP above;
if you mess up and spell it ABS-DUMP it is hardcoded
to go to a physical floppy disk.

Keep your absdump output file in same place your file-save
'tape' lives, and for good luck keep a copy of /usr/lib/pick/pick0
file with them too. {but rename it to foo.pick0 or D3_setup will
suck it in unbeknownst to yourself!}

I think (LL above should be just (L but I'm relying on some
really old notes for this, and I only tested it with (LL so far today...

If you forget to do the T-ATT 512
then it only LOOKS like ABSDUMP went ok;
but when you later use the resulting 'tape', D3 protests
the supplied ABS tape is "too large or too small"

This was a D3/Linux 7.4.2 box, with an activation set to
expire some time in the next 6 months I seem to recall.

Additional wierdness; I hopefully did ./D3_setup with
all the files I'd unpacked back when I first got 7.4.2 loaded,
{last year I suppose,} and just used the standard abs
that RainingData supplied there, but turns out my file-save tape
wasn't the same patch version as that abs. Then I came back
and put my shiny new ABSDUMP 'tape' file on the /v/ folder
and did
d3 -0 -b
and chose (a to suck it in, and found that (f and (x both hung
with some 'illegal activation' message! Had to get out of this
impasse by doing
d3 -k from another screen to croak the hung d3 -0 -b
then {not sure this dd step helped, but it felt Real Good :-) }
dd if=/dev/zero bs=1M count=100 of=/dev/sda99
{except here 99 isn't really what I typed}

then I typed ./D3_setup
and chose 'install with current settings' to get it to relink
the monitor & whatever other arcane initialization that entails.
Again, just to be complete, I reloaded my ABSDUMP 'tape'
into "(a"bs, and reloaded my "(f"ilesave tape. Abs verifies,
and I log into DM with no strange 'illegal activation' probs.
I _do_ need to activate it now, of course...