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D - Real time programming why not?

reply "Mark T" <mt nospam.com> writes:
As you say Not for:
"Real time programming where latency must be guaranteed",

I haven't spent any time with the language except for a quick read of the
DDJ article but D looks a lot like the vapor-ware language I have been
designing in my head for the last year (I am not a compiler writer, I do
real-time programming) except that you have garbage collection. Why couldn't
garbage collection be designed to run as a low-priority background task?
Real time programming requires deterministic behavior but we almost always
have some dead-time. We have recently started to use C++ for real-time
programming and of course we have a very fat programming guidelines manual.

I don't think the language itself has to be open source but the definition
must absolutely be. I like to see both open source compilers like GNU and
commercial ones like Greenhills. GNU keeps the commercial guys "honest".

Either way good luck with your language, the world doesn't need another slow
VM language.

     Mark
Jan 05 2002
parent reply "Walter" <walter digitalmars.com> writes:
"Mark T" <mt nospam.com> wrote in message
news:a181j1$1hj6$1 digitaldaemon.com...
 As you say Not for:
 "Real time programming where latency must be guaranteed",

 I haven't spent any time with the language except for a quick read of the
 DDJ article but D looks a lot like the vapor-ware language I have been
 designing in my head for the last year (I am not a compiler writer, I do
 real-time programming) except that you have garbage collection. Why

 garbage collection be designed to run as a low-priority background task?

Nobody has figured out how to make that work!
 Real time programming requires deterministic behavior but we almost always
 have some dead-time. We have recently started to use C++ for real-time
 programming and of course we have a very fat programming guidelines

 I don't think the language itself has to be open source but the definition
 must absolutely be. I like to see both open source compilers like GNU and
 commercial ones like Greenhills. GNU keeps the commercial guys "honest".

 Either way good luck with your language, the world doesn't need another

 VM language.

Thanks!
Jan 05 2002
next sibling parent "Juarez Rudsatz" <juarez correio.com> writes:
 As you say Not for:
 "Real time programming where latency must be guaranteed",


Maybe this could be changed to : "Real time programming is not in spec, but could be in the future". This could be a point of competition between many implementations of language.
Jan 07 2002
prev sibling parent reply "Mike Wynn" <mike.wynn l8night.co.uk> writes:
"Walter" <walter digitalmars.com> wrote in message
news:a187tl$1lm7$1 digitaldaemon.com...
 "Mark T" <mt nospam.com> wrote in message
 news:a181j1$1hj6$1 digitaldaemon.com...
 As you say Not for:
 "Real time programming where latency must be guaranteed",

 I haven't spent any time with the language except for a quick read of


 DDJ article but D looks a lot like the vapor-ware language I have been
 designing in my head for the last year (I am not a compiler writer, I do
 real-time programming) except that you have garbage collection. Why

 garbage collection be designed to run as a low-priority background task?

Nobody has figured out how to make that work!

Insignia for instance have a fully concurrent garbage collector, the requirement on the OS is that you can place return barriers onto someone elses stack and can see another threads stacks. it is also not as simple as having the GC as a low prority task, there are times when GC much run (if you are geting low on memory becuase there are a lot of unclaimed objects) some of these can be solved by allowing the real time thread to interact with the GC, either triggering it early, or allowing a thread to not be paused for a given time, but there can still be condidtions when the GC will be unable to finish before the realtime thread requires it time slice back. (concurrent and incremental GC do go partway to solving this) there is also problems with heap management, Java had a realtime extension that allowed a thread to preallocate memory (basically a thread local cache) that would the satisfy allocations within a determined time. but only if only that memory was used. depending on how realtime you want to be, you can do it, I wrote, and have seen running a serial UART interrupt handler that was written in Java, It was on VxWork x86 and was used by Insignia as a demo of how realtime Java could be.. policeing the allowable operations was the biggest hurdle in Java. IMHO, if D as a language want to get popular commersial appeal it has to make public the interface to the GC, and allow people access to implement their own GC stratergies. Mike
Jan 21 2002
parent "Walter" <walter digitalmars.com> writes:
"Mike Wynn" <mike.wynn l8night.co.uk> wrote in message
news:a2h51p$1f4p$1 digitaldaemon.com...
 IMHO, if D as a language want to get popular commersial appeal it has to
 make public the interface to the GC, and allow people access to implement
 their own GC stratergies.

There won't be any barrier to this. Even in the alpha version, complete source to the gc is included.
Jan 21 2002