Info about the Burroughs L7000
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Well, although mini-computer is kinda stretching it, "Accounting machine"
selling them short; although they are certainly descended from the
electro-mechanical and hybrid adding machines on steroids that are usually
called accounting machines, they are certainly true computers in their own
right, although certainly configured differently from what we think of
They're an interesting almost completely forgotten and ignored branch of
computing with very little info or even interest out there, illustrated by
fact that even knowledegeable vintage hackers like Bill and Evan don't
know what they actually are.
Although Olivetti, NCR, Monroe and others were also major players,
for a long time the leader in accounting machines, found in every bank
and the offices of most medium sized businesses. While IBM was focussed on
punched card batch processing machines Burroughs et al were providing
to do the same sort of thing in real time with direct operator input.
Originally the machines were completely mechanical except for an electric
to drive and turn the hundreds of wheels, cams and levers that did the
calculation and printing on ledger cards and journal rolls; this was the
Burrough 'F' series, programmed with metal pins of different lengths and
locations in exchangeable "program panels."
As solid state technology became available some of those wheels, cams and
were replaced with transistors and core memory, and then integrated
this was the Burroughs 'E' series, programmed with metal pins and wired
board programming panels.
Then Burroughs brought out the 'L' series, programmed in 'SL3' and 'SL5'
assembler (System Languages), which ranged from the original L2000 to the
before the ledger cards were finally abandoned and the B80 replaced them
disk-based systems programmed in high-level languages, mostly Cobol.
About the only thing that the L series had in common other than appearance
the fact that they all had an integrated paper tape reader beside the
for loading firmware and application and utility programs. Up to the L5000
system memory was actually a small fixed disk while from the L6000 onward
consisted of 2KB memory cards; also the keyboard and PPT reader were
through the 5000 and electronic after that. Although not all models did,
were mainly intended to use ledger cards and had split platen printers with
separate ledger card feeder so that the printer was actually three separate
printers in a way, using a Selectric-style golf ball until the L9000
went to a dot-matrix printer (and sacrificed the red/black dual color
capability). The ledger cards could have magnetic stripes on the back which
stored account names etc. and account balances and allowed for automatic
insertion and alignment (although the mechanical machines could also align
cards by punching little notches).
A full-blown L could have magnetic stripe ledger I/O on the console with or
without an optional auto-feeder/stacker, and a free-standing separate
auto-reader that could process a stack (probably what Bill is thinking of),
to four digital cassette drives, a paper tape and edge-punched card reader
punch, an 80 or 96 column card reader and punch, and even datacomm and a
display on the latest models. No workstations plugged into an L, it *was*
workstation, although some models could connect to a 'real' mini or
I have a picture here of an L with all the bells and whistles; I'll try to
time to scan it.
Unfortunately there is almost no firmware or software around except for
sometimes found in the back of the machine with the print set, or the
unfortunately rare DC300 cartridge that can still be read. Ironically the
hard-disk based units are more likely to be operational while the
based units are of course huge bricks without the firmware to boot them up.
There are a few others out there that I know of, although AFAIK the only
that actually works (or did at one time) is a restored L5000 at Bletchley
The odds are against it, but I'll certainly cross my fingers for ya that
it going when you get it. The most crucial part is that DC300 if there is
if the band hasn't rotted, the oxide crumbled or stuck together etc. and if
L actually did completely and successfully dump a memory image to it the
time it was shut down, then you just might be in business. If there
one, then remove the cart and inspect/repair/clean it as much as possible
you turn on the machine; on power-up it will automatically try to read that
cartridge and could quite possibly destroy it if it's in bad shape.