The Jim Austin Computer Collection
Powers-Samas Tabulator
This
is an example of a mechanical computer. It is probably dated before 1950, but I
have no details. There is no name plate on the machine.
The
machine is owned by the London Science Museum, it was lent to ICL in 1988 then given to
the collection by mistake. The machine is now on display in the Computer
Science department at York University.
The
machine was altered for display, probably by ICL. It came from Fujitsu in there
offices in Bracknell, found and donated by Hamish Carmichael.
The
machine is used to read and print the contents of cards. It can also add up the
values on the cards and print the totals out.
A note from Dennis
Hart on the machine...
"Your photo looks like a 36 column sorter
in use till the early 50's and was replaced with the 40 column system the
card size was about the same with extra columns and an extra row to allow
for full alpha punching.I was a field engineer with Powers Samas from 1951
to 1971 having worked on 21 col 36 col 40 col 65 col and 80 column systems
then untill about 1990 I worked as an independent engineer servicing the old
mechanical equipment for customers who were not ready to go electronic.Your
photo of the tabulator looks like a 65 column model again replaced with the
80 column and early electronic equipment I think the 40 column systen out
lasted the 65 & 80.I converted many tabulators from £.s.d. to decimal on the
early 70's.
I do not know any way to accurately
date the sorter. Check to see if it is a 36 column. lift the glass cover lid
over the sensing pins and on the left chrome bar there will be a scale 1-36
or 1-40 as I said if it is 36 then these went out in the early 50s the 40
column range I worked on as late as 1990/91-but have now long since
scrapped all my parts books and operators manuels. If the card has wrecked
under the sensing pins U must wind the pins up by hand so that they are
clear with small driver inserted between the feed rollers-to open them up
slightly use a wreck knife (which I dont suppose you have) to remove the
card I might still have one. These old machine ran at about 400 cards per
min the later ones at about 650 so the feed settings have to be very
accurate-the card pick up knife 4.5 thou and the gap for the card to go
through abouit 9.5 thou but why did it wreck in the first place dirt
incorrect feed settings etc. Many public libraries all over the country used
these sorters for keeping check on lending books"
Dennis Hart 13 July 2008
The
following is a copy of an email from Robin Hill, who
used this type of machine and nicely places it into context:
"The machine is
quite complex. It takes cards in from this side, the cards are shown in blue in
the middle (see below). These come out on the other side of the machine.
I started vac work with Vickers
Armstrongs (Aircraft) Ltd at Weybridge in 1953 (while at London Univ '53-'56).
After graduation in 1956 I joined them full-time as a statistician
in the Design Office before helping set up an Organisation
& Methods Department. Attended at that time was what I believe was
the first 8 lecture evening course in systems analysis and design at City
University - using Fortran examples. Some time after that F R
Brown gave a week's course at Oxford on Mathematical Forecasting as
Scientific Management began to emerge. It was in the later
'60's, using Cobol and a rented ICL 1901 machine with 8k (perforce
enhanced to 16k!) magnetic core memory that workable factory scheduling
systems were implemented for Birds Eye Foods (the company's first computer
application).
The aircraft industry were heavy on office
automation and mathematical calculation and particularly receptive to new
inventions because of the science-based nature of the business, not to say the
predominance then of cost-plus defence contracts! In the
1950's/'60's Powers Samas was a wholly-owned subsidiary of Vickers Group, the
subsidiaries in Aircraft, Shipbuilding and Engineering were therefore handy
test-beds for Powers-Samas equipment with their heavy data volumes and
extended coding structures. I transferred to Powers Samas
Accounting Machine (Sales) Ltd from Weybridge as a sales engineer in August
1958, located at the principal London Sales Office at 88 High Holborn, which
also housed the main Powers Training Centre. It was rather more than a
year later that Powers Samas was subsumed into ICT (later ICL). I left
to join Peat, Marwick Mitchell as a consultant and became an early member
of the British Computer Society in about 1961.
If memory serves Hollerith had invented punched
cards for use in the US census in the 30's, based on a card
containing 80 vertical columns of thirteen positions in which the figures 0
- 9 alone or, combined with three top edge overpunching positions, gave
alpha-numeric representation. (I think their over-punches were labelled X,Y
and Z, but can't now be sure). This equipment was marketed by
British Tabulating Machines (BTM) in UK. It relied upon rectangular
perforations allowing 80 electrical brushes to make/break contact as each
card fed top edge first. The columns of the card were
allocated to 'fields' of data which, with a descriptor, were usually
pre-printed onto the card. Each job thus had its predefined dataset
comprising one or more cards into which the data were punched. When
'read' by machine, electrical connection prompted actuation of standard
machine features such as a printhead or counter via a removable code
panel using double-ended leads to set up appropriate connections to translate
the sensed codes. While ostensibly offering flexibility for
connection changes, such was the complexity of wiring needed for most jobs that
pre-plugged panels were kept for all but the simplest routines. By
their nature the mechanical components of the Hollerith machines were
relatively expensive to produce, with squared holes which needed to be
broached. Positions allocated needed to be sufficiently spaced and sized
as to allow good electrical contact without interference. In contrast, no
doubt for patent reaons, but also perhaps reflecting British and
Vickers mechanical engineering heritage, 'Powers' machines opted
for round perforations and mechanical machine actuation. Round holes
could be more cheaply drilled, and closer proximity achieved without
interference. This meant that the standard Hollerith-size card could be used
to carry 90 data columns - a marketing plus. Later this was further
enhanced with the successful introduction of intermediate punching effectively giving
180 columns.
The Tabulator was, of course, central to any
punched card installation - the central processor. The front card
hopper on the Powers Tabulator fed cards top edge first into a
machine track between drilled blocks containing as many rods
as there were hole posions in the card. This permitted rods to be
forced down wherever coincident with a punched hole in the card. This was
achieved by locating bove the reading block, in contact with the tops of the
matrix pins, a removable Y-shaped 'connection box' (equivalent to
the Hollerith plug board) which was hard-wired spcifically to the job.
The box had at the base as many rods as were needed to read the positions
within the used data fields, so that, when forced down, appropriate
features of the machine - printheads, counters or control links were
physically set as a reaction to the moving tops of the connecting box rods.
Thus while many connection wires were straight-through, some sensed holes
needed to allow multiple actuation, while some multiple code-punching
needed to be combined to achieve a single purpose.
Designing the system including 'programming' the tabulator was the sales
engineers job, while soldering the 'conn-box' forest of cranked rods to
meet the design requirement was down to the skill of the Powers Engineer who
was thus the doyen of the machine room.
Each machine cycle first fed a card, next
forced down the rods and pins to set the mechanisms (e.g. throwing
up a hundred or more foot-long character bars), then executed the
settings (e.g. simultaneously banging hammers on print heads to
force them onto a typewriter ribbon to impress onto the paper beneath), and
then feed out the card as the next fed in. Given all the metal on
metal, the cranking of hundreds of rods, and hammering of printheads,
noise levels in a machine room with a dozen or more tabulators (plus sorters
etc.) can perhaps be imagined. Mechanical wear and tear was heavy
requiring constant engineering maintenance, while card consistency and
handling were also critical - extracting a 'card wreck' from the machine and
trying to piece it together sufficiently to be able to reconstitute that data
was the constant fear - bad enough on tabulators, but worse on high-speed
sorters where one hiccup could destroy many cards and several hours work.
A special flexible steel hook-ended wreck knife was available (a must for your
collection!) A later tabulator refinement was the replacement of
mechically thrown character bars with multiple wire character
imaging printheads to increase speed and reduce noise levels and wear. Later
tabulator models also sought to replace soldered rod conn boxes with
bowden cable boxes to allow greater flexibility for change, but by then
electronics were already having an impact.
The Powers tabulator could be fitted with an
ancilliary mechanical device called a Summary Punch. This was wheeled up
to and attached to the back of the Tabulator so that when totalling was
actuated a mechanical connection actuated the Summary Punch, punching
the results into a fresh card. Up until that point multi-stage processing
of data necessitated tabulating all cards several times with
or without intermediate resorting. With a card for each line entry this could
be a massive burden in high volume applications. A further development,
and the first step towards stored program computing, was the Powers
Electronic Multiplying Punch (EMP). Instead of punching a mechanically
derived result relayed from a Tabulator, this was able to read and retain factor
data from the lead card of a set fed into it conventionally and apply it to variable
data in succeeding transaction cards via valve-based electronics,
punching the results into those cards while also summary punching identified intermediate
or tralier cards of the set. However, the basic speed limitation of
machine cycling remained.
During the mid '50's and '60's Powers had begun
addressing electronics more seriously at Whyteleaf in Surrey. Its
first attempt at a stored program computer was the Program
Controlled Computer (PCC). The first machine I think went to Bristol
Council, while the second came to Vickers at Weybridge in about 1957/8.
Only machine code was available and programming was by means of
copper rivets installed into a removable fibre board which I seem
to recall allowed about 22 program steps. I/O was punched cards
with processed data recorded to a magnetic drum, which involved timing each
read/write instruction. Like the EMP this had valve electronics but
resembled a diesel rail engine with a cooling system which sounded like
Niagara Falls. The machine was never likely to be viable. In
parallel, Stress engineers at Weybridge were making some
progress with an early Elliott machine applyiedd to mathematical
computation. I know no details except that it was possibly an 803 or it
may just have predated that model.
For tackling the vast potential of the beckoning
Electronic Age Whyteleaf had turned its attention to grander things and a
sales briefing meeting was organised in about 1957 to equip us to sell the
Atlas - a 'proper' large-scale computer design which, despite the
glamourous artists impressions, so far as I know was never actually constructed. Unlike
the ill-fated Elliott 405 of the time of which one was actually installed at
great expense at Watford for Radio Rentals, but this never processed a
byte in anger before being trashed. Aside from pioneering analysis and
programming difficulties, a serious limitation for it, as for all
machines then was I/O. 80 column punched cards were the preferred
choice for pre-loading programs but punched paper tape quickly superseded
punched cards for keyed data using teleprinter 8 channel tape.
Teleprinters were also much commissioned for punched data output to feed line printers
(developed from tabulators) which tended to be buffered off-line. The
introduction of magnetic media and internal storage quickly transformed this
scenario as did such techniques as print spooling.
Returning to punched cards I seem to have heard
that Powers had at one time tried the introduction of a half-length card of 45
columns but cannot be sure. It did have a downsized (in both
dimensions) card in the '40's with 36 columns, but this later
changed to 40 columns. This was particularly successful in business,
rather than engineering, situations, especially accounting and retail markets,
which were transaction-volume rather than data-complexity driven. Its
commercial success waned as the electronic revolution dawned, but it was
greatly loved by staff and customers alike. So much so that
somewhere round 1960 IBM (successor to BTM) tried to introduce a 36
column range (System 11?) but was unable to bring it successfully to market.
The most lowly piece of equipment in the punched
card range (after the wreck knife) was the hand-punch, a small flat-bed
device with a ratcheted sliding bridge carrying button-topped spring-returned
dies - one for each of the thirteen punch positions, with a tangential
ratchet-actuating button. Cards were inserted singly with one
hand as the other drew back the bridge to the first column, the
keys were then operated with fingers of the second hand in rapid
combination ending with the ratchet key to move the bridge to
the next column. This required battery-hen mentality, extreme manual
dexterity and enough finger strength to push each die fully home
(otherwise 'hanging chads' resulted which we all know about from
Florida!)
The automatic punch was a sit-at machine which fed
cards in succession automatically from a hopper along an extended bed
end-to-end, while the keypad caused electrical actuation of the dies reducing
the danger of imperfect perforation. A typewriter-type tab mechanism
enabled skipping over fields where all were not required to be punched and for
carriage return. Some female operators were capable of quite suprising
punching speeds. I cannot now recall particular records but they
were perhaps double the planning average used when calculating equipment
needs which, I seem to recall, was 11,000 key depressions per hour - and
repetitive strain injury was unheard of in those days! (not to say though that
it didn't occur).
Sorters were piano keyboard style machines with a
hopper to the left feeding under a read head onto a roller-bed which
carried cards over the top of hoppers at high speed. On feeding, the
sensing of a perforation caused the appropriate trapdoor to flip up
ready to 'capture' the card as it reached that pocket, unperforated cards
dropping into the last hopper. Sorting was in ascending order of column of
the field containing control data - one pass for each numerical
column, or two for alphabetical or coded data. Pick-up accuracy and
ability to remember just where one was in multiple sorts were, of course,
vital - especially if a high volume sort was entailed.
These recollectionsl may be incomplete or
faulty in some respects as quite a few years have rolled by, but I will
examine your site more thoroughly, and search my (often consolidated and
moved) belongings for any remaining relevant memorabilia, and perhaps
respond again in a more considered way."
Robin Hill, Norrköping,
Sweden, 2005.
Here are the photos of the machine
when got it:

The machine is run from a motor in the box at the bottom. The
handle on the right (above) is used to hand crank the machine.
The box with the rods in (see below, right) is the programming
box for setting up the machine.

Above left shows the printer mechanism.
The picture below shows how complex the machine is.
