Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!sics.se!fuug!field!antu From: antu@field.fi (Antero Markkula / Systems) Newsgroups: comp.realtime Subject: Re: Summary of opinions and info on realtime kernels (long) Keywords: more subjective than factual Message-ID: <1991Jun6.065053.20411@field.fi> Date: 6 Jun 91 06:50:53 GMT References: <571@ceco.ceco.com> Organization: Field Oy, Helsinki, Finland, Europe Lines: 81 Here comes some additional (subjective) information on realtime kernels. There is an excellent concept for people, who want to make distributed applications using 68k / 88k -based VME/VSB processor boards. This concept is Motorola Computer Systems's VMEexec. The realtime kernel currently used (but not limited to) is SCG:s pSOS+ , multiprocessing version. Program development is done using Motorola Delta series Unix computers or AT micros (Philips). Downloading is done through ethernet or/and VMEbus. Ethernet targets can be shared by several programmers without shutting power down from the Unix computer several times every day, when different boards are tested, which is the case if targets reside in host. 68k and 88k systems can be mixed in an application. User interface is Xwindows, debugger is XRAY's special version with remote debug / monitoring capability. SCG's pPROBE is a valuable addition to the testing environment. Tools to build applications are menu driven and fast to use. Tasks can be boot resident and also loaded dynamically. There is also a makefile generator mkmk for easy integration of own C programs. The realtime application can communicate with Unix V using SVIDlib library. Communication can transparently happen both using VMEbus and ethernet. SVIDlib also makes it possible to port Unix applications to the realtime world. The realtime applications can be prommed, or booted from Unix or local disk, or finally from ethernet. Ethernet support includes TCP/IP portable streams. Standardisation VITA (VMEbus Trade Association) has provided a document called ORKID (Open Realtime Kernel Interface Definition), which is similar to SVID, but proposed for a realtime standard. ORKID defines the following (kernel independent): 1. Task control 2. Queues for multiple task priority management 3. Semaphores 4. Clock and timer controls 5. Memory allocation facilities 6. Hardware interrupt support facilities 7. Event flags 8. Expections handling mechanisms 9. General system administration functions. Moving from a single processor system is very straightforward; basically You have to flag the necessary local objects to global. The POSIX committee for realtime extensions - P.1003.4 - also assigned the ORKID members with document to the P.1003.13 - Realtime Applications Study Group. So, POSIX and ORKID integration means faster standardisation process. The VMEexec targets range from about 2 MIPS MVME107 (68010) to the new 32 MIPS MVME187 (88100) SBC. To summarize, why VMEexec is a good solution for realtime applications: - based to standards (SVID, ORKID/POSIX, X11, TCP/IP, VMEbus) - economical development environment (Mot. Delta or Philips AT) - fast design cycle - supports from single cpu embedded applications to large multiprocessor distributed unix / embedded applications (from small machine control to huge aircraft simulators) DISCLAIMER: These opinions are my own - even if they may be shared with many others ! Antero Markkula E-Mail: antu@field.FI Department manager/Systems, Field Inc. Telex : 122022 field sf Fax : +358 0 798853 Phone : +358 0 757 1011 "We are what we are and it's never enough" - Chris de Burgh -- Antero Markkula E-Mail: antu@field.FI Department manager/Systems, Field Inc. Telex : 122022 field sf Fax : +358 0 798853 Phone : +358 0 757 1011