ACE Machine
Allan Turning
UNIX and C
Dennis Ritchie
Kennith Thompson
Dennis Ritchie and
Kennith Thompson, pioneers
Of UNIX and C
Kennith Thompson, pioneers
Of UNIX and C
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.
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
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
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.
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.