Drobe :: The archives
About Drobe | Contact | RSS | Twitter | Tech docs | Downloads | BBC Micro

Reply to thread

AW: "instead of going about it top-down and presuming the applications must be changed how can people change the OS to account for non-multithreading applications?"

The approach I've taken with ROLF is to start with the equivalent of the RO polling system, but extended it to allow new applications to make use of the underlying preemptive scheduling and asynchronous I/O from Linux.

Specifically, there's still Poll and PollIdle (called PollWait), which block the calling thread until the Wimp sends it an event, but there are also two more functions, Detatch and PollActive, which allow the calling thread to keep working while waiting for events from the Wimp. The former detatches the process from the Wimp so it can do anything non-screen related in the background and be informed of pending Wimp events by a signal (or selected file descriptor), the latter allows the process to continue working while waiting for the Wimp to authorise screen-related activity by the process. Also, screen redraws are requested of processes in parallel (one outstanding rectangle redraw per process).

Since the kernel is Linux, processes can also start threads, but the above allows a lot of flexibility without needing the complexity inherent in threads.

 is a RISC OS UserStoppers on 28/10/08 10:33AM
[ Reply | Permalink | Report ]

Please login before posting a comment. Use the form on the right to do so or create a free account.

Search the archives

Today's featured article

  • Voting for Best of 2004 Awards open
    Let the people decide - ends 30th Dec
     25 comments, latest by davehigton on 27/12/04 10:34PM. Published: 10 Dec 2004

  • Random article

  • Repairing, restoring legacy Acorn kit
    All the gory photos online
     8 comments, latest by Timothy609 on 29/7/03 7:35PM. Published: 28 Jul 2003

  • Useful links

    News and media:
    IconbarMyRISCOSArcSiteRISCOScodeANSC.S.A.AnnounceArchiveQercusRiscWorldDrag'n'DropGAG-News

    Top developers:
    RISCOS LtdRISC OS OpenMW SoftwareR-CompAdvantage SixVirtualAcorn

    Dealers:
    CJE MicrosAPDLCastlea4X-AmpleLiquid SiliconWebmonster

    Usergroups:
    WROCCRONENKACCIRUGSASAUGROUGOLRONWUGMUGWAUGGAGRISCOS.be

    Useful:
    RISCOS.org.ukRISCOS.orgRISCOS.infoFilebaseChris Why's Acorn/RISC OS collectionNetSurf

    Non-RISC OS:
    The RegisterThe InquirerApple InsiderBBC NewsSky NewsGoogle Newsxkcddiodesign


    © 1999-2009 The Drobe Team. Some rights reserved, click here for more information
    Powered by MiniDrobeCMS, based on J4U | Statistics
    "I made the assumption, though I should have known better in view of previous experience, that the article was factual"
    Page generated in 0.0543 seconds.