there was a machine
THE SEAC
by IDA RHODES
Say it’s weary, say it’s slow,
Say that luxury ignored it,
Say it’s growing old, but know
We all adored it.
SEAC was born on the wrong side of
the tracks with only 11 commands and 512 storage registers, but in the hearts
of its grateful users this prodigy has left a glowing spot that none of its
opulent, sophisticated successors will ever dislodge. In fact, I often shed a tear for the nouveau
riche programmer: a programmer who is unable to communicate with his
machine in its own natural language, but must instead transmit his intent in
the alien speech of the Court; a programmer who is denied the thrill of
personally wielding a tremendously powerful, yet utterly compliant, tool; a
programmer who is bereft of the mentally invigorating need ever to explore new
means for squeezing a maximum of information into a minimum of storage space; a
programmer who is deprived of the privilege to effect ameliorating changes in
the structure of his machine.
Ere future generations venture to
sneer at SEAC’s operational speed of one millisecond for addition and three for
multiplication, let them ponder over those sweet uses of adversity from which
the pioneers in electronic computation derived such huge benefits. SEAC’s devotees could rightfully assert that
it was the first device in this country to function with an automatically
sequenced, internally stored program, but that claim would be based on a
technicality. Much of its success must
be credited to the advances made by previously conceived instruments, whose
gestation periods were necessarily prolonged because of their higher degree of
sophistication and more ample physical endowment. But we do claim with gusto that its features
have been a source of ease and comfort to the tyro programmer and coder.
Take for example its four-address
system, which in the early stages was SEAC’s only mode of control. What could be a more natural bent for the
coder than to direct the machine to perform a basic process on a pair of
operands located at the first two addresses, to store the result at the third,
and to look for the next command at the fourth? If it were found necessary to omit, or to
alter the sequence of, a set of instructions, a readily effected change in the
fourth address of a command or two would correct the routine at once. Additional aid was granted by the fact that
SEAC needed only one command for reading into the storage, and again only one
command to write out.
Humble SEAC’s time was so inexpensive
that the coder could frequently allow himself the luxury of code-checking and
correcting his routine all in one run. Since each command bore a break-point bit, key
instructions were usually coded with it. If a routine ran into trouble, a flick of a
console switch caused the result of every such instruction to be printed out. In dire distress, the coder could, by a switch
setting, automatically monitor the results of every consecutive operation. With what dignified silence has our noble SEAC
borne the base canard that its mercury tanks were misbehaving - a pretense so
often voiced by the human bungler as he resorted to that all-too-handy switch!
SEAC’s users enjoyed a priceless boon
in the constant presence of its creators. Not only did these magicians watch
unceasingly over their brainchild, but graciously permitted us to offer
suggestions, while they continuously introduced improvements that amazed and
delighted us. The SEAC of today bears little resemblance to the immature
fledgling of 1950; and as it grew and developed, so did the skill and
confidence of the pioneer coder. That Spartan individual was never compelled to
swallow the predigested pap prepared by the Higher Caste for the benefit of the
Untouchables. He knew the precise location and function of every bit in his
routine, and he learned to manipulate the computer with the same care and
reverence that a dedicated musician accords the instrument of his choice.
Now that SEAC has passed into glorious
history, let a tender tribute be recorded for posterity to this superbly
diligent, faithful, and efficient servant that so frequently doubled as a
serenely patient and exceedingly effective trainer.
The SEAC
From Datamation (a defunct computer magazine),
September 1964