2 ms·

Concurrent Pascal and SuperPascal programming languages

58 points by Rochus 3y ago

rossjudson 3y ago
Some of the earliest papers here (1966!!) document histories that are too easy to lose. Reproducible testing of monitors (1978!) outlines test creation techniques that are still in use today.
lukego 3y ago
The Architecture of Concurrent Programs (his book) is a real treasure. I read that on a tip from Ralph Johnson way back when on the C2 wiki. Special purpose operating systems e.g. with disk driver (for input) and a compiler (the application) and a printer driver (for output.) Those were the days!
Rochus 3y ago
The SuperPascal paper was submitted to the IEEE Software journal 30 years ago in November 1993; it appeared in the May 1994 issue. SuperPascal was also remarkable because it (together with his previous language Joyce) manifests a paradigm shift by Per Brink Hansen from the monitor to the CSP channel concept. The latter is prominent today because it is also used in the popular Go programming language.
mrkeen 3y ago
http://brinch-hansen.net/papers/1999b.pdf http://brinch-hansen.net/papers/1999b.pdf > Hoare (1972) had introduced the concept of a conditional critical region that is delayed until a shared data structure satisfies a Boolean condition. In a shared class, I expressed the same idea by means of an await statement, which can occur anywhere within a critical region (Brinch Hansen 1972). > At the time I was concerned about the inefficiency of conditional critical regions which retest Boolean conditions repeatedly until they are true. As an alternative I decided to let the programmer control the frequency with which scheduling expressions are reevaluated. I did this by associating explicit queues with shared variables. Critical regions can delay calling processes in these queues and resume them later (Brinch Hansen 1972). public void send(int m) { while (full == max) await(e); This ended up as a feature in software transaction memory as the 'retry' function - without the inefficiency of busy-waiting and without the programmer needing to pick a frequency of scheduling: send m = do when (full == max) retry https://hackage.haskell.org/package/stm-2.5.3.0/docs/Control-Monad-STM.html#v:retry https://hackage.haskell.org/package/stm-2.5.3.0/docs/Control... > Retry execution of the current memory transaction because it has seen values in TVars which mean that it should not continue (e.g. the TVars represent a shared buffer that is now empty). The implementation may block the thread until one of the TVars that it has read from has been updated.
layer8 3y ago
Is SuperPascal superscalar? It’s almost an anagram. ;)

58 points by Rochus 3y ago

Some of the earliest papers here (1966!!) document histories that are too easy to lose. Reproducible testing of monitors (1978!) outlines test creation techniques that are still in use today.

lukego 3y ago

The Architecture of Concurrent Programs (his book) is a real treasure. I read that on a tip from Ralph Johnson way back when on the C2 wiki. Special purpose operating systems e.g. with disk driver (for input) and a compiler (the application) and a printer driver (for output.) Those were the days!

Rochus 3y ago

The SuperPascal paper was submitted to the IEEE Software journal 30 years ago in November 1993; it appeared in the May 1994 issue. SuperPascal was also remarkable because it (together with his previous language Joyce) manifests a paradigm shift by Per Brink Hansen from the monitor to the CSP channel concept. The latter is prominent today because it is also used in the popular Go programming language.

mrkeen 3y ago

http://brinch-hansen.net/papers/1999b.pdf http://brinch-hansen.net/papers/1999b.pdf > Hoare (1972) had introduced the concept of a conditional critical region that is delayed until a shared data structure satisfies a Boolean condition. In a shared class, I expressed the same idea by means of an await statement, which can occur anywhere within a critical region (Brinch Hansen 1972). > At the time I was concerned about the inefficiency of conditional critical regions which retest Boolean conditions repeatedly until they are true. As an alternative I decided to let the programmer control the frequency with which scheduling expressions are reevaluated. I did this by associating explicit queues with shared variables. Critical regions can delay calling processes in these queues and resume them later (Brinch Hansen 1972). public void send(int m) { while (full == max) await(e); This ended up as a feature in software transaction memory as the 'retry' function - without the inefficiency of busy-waiting and without the programmer needing to pick a frequency of scheduling: send m = do when (full == max) retry https://hackage.haskell.org/package/stm-2.5.3.0/docs/Control-Monad-STM.html#v:retry https://hackage.haskell.org/package/stm-2.5.3.0/docs/Control... > Retry execution of the current memory transaction because it has seen values in TVars which mean that it should not continue (e.g. the TVars represent a shared buffer that is now empty). The implementation may block the thread until one of the TVars that it has read from has been updated.

layer8 3y ago

Is SuperPascal superscalar? It’s almost an anagram. ;)