| Computer
History - Inventors |
| ACE
Machine |
Allan Turning |
ACE
the
'automatic computing engine'.
August 1947, it was announced that a 'pilot' ACE would be built. The
machine ran its first program in the May of 1950. The Pilot
ACE was heavily influenced by the type of hardware available
and
the need to be fast and efficient. The memory was based on acoustic
delay lines. Bit streams were stored by converting them into sound
pulses which circulated in a mercury delay line.
The operations of the Pilot ACE allowed the programmer to specify move
operations from one delay line to another. This was achieved by waiting
for the number to come round and then 'gating' it into the data flow of
another delay line. Because it was arranged so that the numbers emerged
from the delay lines at the same' moment, you could only move the 9nth
number in a delay line to become the 9nth number in another delay line.
If you wanted to change the order of numbers in the long delay lines,
you had to first transfer the number to a short delay line and then
wait for the position in the destination to come round.
|
The
main store of the machine used 10 delay lines each holding 32 words
of 32 bits. There were also six temporary stores implemented as short
delay lines each capable of holding a 32-bit number.
In the years 1952 to 1955, the Pilot ACE was the fastest computer
available and the NPL became a world centre for numerical mathematics.
Because so many programs were available for the Pilot ACE, and the NPL
provided computing to government and industry, English Electric decided
to build a commercial version of the Pilot ACE. They added a magnetic
drum, which fitted in with the circulating store principle of the delay
line, and increased the power of the machine. The commercial
Pilot
ACE was called the DEUCE, and one of the first was installed
at NPL
in 1955.
This had a 48-bit word size, but still used delay I lines for storage.
It could multiply two numbers in .5ms and it contained 7,000 valves.
The ACE was completed in 1957
32 of the commercial versions, the DEUCE, were sold another derivative
of theACE, the BendixG-15, sold more than 400 units |
|
|
| UNIX
and C |
Dennis Ritchie
Kennith Thompson |
Thompson
found an obsolete PDP 7 mini computer He added a fancy
graphics terminal to it which had been discarded from a mainframe and
the pair then started work on their operating system. It wasn't exactly
easy because the PDP 7 wasn't self-sufficient, so they had to use a PDP
7 cross assembler that Thompson wrote for a GE mainframe. Most of the
actual work on the operating system was done by Thompson, but Ritchie
contributed the theoretical ideas that helped shape the form of the
filing system.
After two years of work the operating system had outgrown the PDP 7 and
they had their eye on a PDP 11. This could be regarded as the
forerunner of the personal computer, having a small but neat
architecture which had enough power to run interactive software.
However, they couldn't propose that Bell give them a PDP 11 to develop
an operating system because the memory of the Multics failure was still
in the air. Instead they suggested what today we would call an office
automation system for the patent department
The first stage of the office automation system was to implement Unix,
as it was called by then. With the experience that Ritchie and Thompson
already had, this didn't take long. They soon had a working system and
their first users, and the operating system became increasingly popular
at Bell.
In 1972 Thompson started work on Belle, a chess-playing program that
used traditional search techniques combined with a database of end
games. Later, in 1976, he and Joe Condon developed a hardware prototype
for a move generator for Belle possibly the first dedicated
chess-playing hardware. By 1980, this had developed from a 200 move-per
second machine to 120,000 moves per second. This fast machine used
1,700 chips and did all the work necessary to play top-class chess.
Earlier Versions had used a PDP 11 as a host, but the 1980 version of
Belle did everything itself and won three ACM computer chess
championships (1980, 1981 and 1982). It made history for being the
first program to be awarded the title of 'Master' in the US
Operating systems had traditionally been written in assembly language
because they needed the speed this conferred. Not only did an operating
system seem to need an assembly language, it also meant getting deep
into the workings of the machine's hardware.
The pair attacked the problem in two ways. first they decided to create
a new high-level language that would be close enough to the underlying
machine architecture to be efficient. Then they would rewrite Unix with
the highly machine-dependent and speed-critical parts together.
Ritchie set to work on the language problem, basing his design on
another language called BCPL, a systems implementation language
invented in the UK in 1967. Thompson had already implemented an
experimental language based on BCPL for the PD P 7 system running under
the first version of Unix (1970). This was called B and is best
described as a stripped-down version of BCPL. The switch to the PDP 11
and the need for a system implementation language for the next version
of Unix set Ritchie to work on converting and extending B. The main
change he made was the addition of data typing to accommodate the
broader range of storage types and operations avail able on the PDP 11.
But the changes were large enough to merit a new name and after B comes
C
From being a language running under Unix, C turned into the language
that Unix was written in. The machine-dependent and other critical
sections of the code were grouped together and written in Assembler and
known as the mnel. The rest of the operating system around 90 percent -
was written in C. This resulted in the first portable version of Unix
and marked the start of its wider- acceptance.
In 1983 Dennis Ritchie and Kenneth Thompson received the Turing Award
from the ACM . The citation read: the success of the Unix system stems
from its tasteful selection of a few key ideas and their elegant
implementation. The model of the Unix system has led a generation of
software designers to new ways of thinking about programming. The
genius of the Unix system is its framework, which enables programmers
to stand on the work of others. |
 |
|
|
 |
View CPU Pictures |
|
CPU Specification List |
|
CPU
History |
|
Software History |
|
Hardware History |
|
Computer History |
|
Technical Terms (glossary) |
|
 |
1975
Steve Wozniak
and
Steve Jobs
start Apple Computers inc. |
 |
1978
Apple II Released |
 |
1993
Power PC is released |
 |
1975
Paul Allen and
Bill Gates
start Microsoft Inc. |
 |
1977
Commodore PET |
 |
1985
Commodore is released |
|
