leo@aai.com (05/10/91)
The EISA support update says it's ONLY for EISA bus computers. The kconfig options only mention 4M, 8M, and 16M. Will ISC use any memory over 16M on an ISA machine, or is it ignored? Is there some other update that addresses this? Will the EISA update work on an ISA machine? Thanks for any info! -- Leo leo@aai.com leo%aai@uunet.uu.net ...uunet!aai!leo
cpcahil@virtech.uucp (Conor P. Cahill) (05/11/91)
leo@aai.com writes: >The EISA support update says it's ONLY for EISA bus computers. The kconfig >options only mention 4M, 8M, and 16M. Will ISC use any memory over 16M on >an ISA machine, or is it ignored? Is there some other update that >addresses this? Will the EISA update work on an ISA machine? No. The problem is that DMA will not work from a device on the ISA bus to memory above 16MB. -- Conor P. Cahill (703)430-9247 Virtual Technologies, Inc. uunet!virtech!cpcahil 46030 Manekin Plaza, Suite 160 Sterling, VA 22170
richard@pegasus.com (Richard Foulk) (05/13/91)
>>The EISA support update says it's ONLY for EISA bus computers. The kconfig >>options only mention 4M, 8M, and 16M. Will ISC use any memory over 16M on >>an ISA machine, or is it ignored? Is there some other update that >>addresses this? Will the EISA update work on an ISA machine? > >No. The problem is that DMA will not work from a device on the ISA bus >to memory above 16MB. Okay, so ISC blew it. It IS possible to run ISA bus Unix with greater than 16 megs of memory. DMA is not a necessity. I've seen people reporting 24 megs and more, in this forum, on ISA bus machines. So what is the real situation today? Which 386 ports of Unix will support greater than 16 megs on the ISA bus? (Did the MEMRANGE spec actually vaporize with ISC's 2.2, or is it just hiding somewhere else?) -- Richard Foulk richard@pegasus.com
cpcahil@virtech.uucp (Conor P. Cahill) (05/13/91)
richard@pegasus.com (Richard Foulk) writes: >Okay, so ISC blew it. It IS possible to run ISA bus Unix with greater >than 16 megs of memory. DMA is not a necessity. I've seen people >reporting 24 megs and more, in this forum, on ISA bus machines. I wouldn't say ISC blew it. The original System V 3.2 only supports up to 16 MB and requires changes to support additional memory. Somewhere along the way ISC decided that the market for >16MB on an ISA bus is too small to justify the additional effort required to support it. As far as I know, SCO is the only vendor to support > 16 MB (although I don't know if it will work on ISA bus systems, but I think it will). SCO did this by using the "epanded memory" trick that is used by many dos systems (it copies a page down below 16MB whenever a page is accessed by a bus operation). This works the same way under EISA systems, even though it isn't necessary there. On the other hand, ISC has committed to supporting > 16MB on many EISA systems in full native mode in release 2.3. (An update disk that works for several EISA MBs, but fails on some others is available. A more general one is in the works - no word on the actual release date). >So what is the real situation today? Which 386 ports of Unix will support >greater than 16 megs on the ISA bus? (Did the MEMRANGE spec actually >vaporize with ISC's 2.2, or is it just hiding somewhere else?) The MEMRANGE spec went away in 2.2, but I don't think it worked correctly in 2.0.2. We set up a system with 32MB of memory and a 12MB ram disk. When we went above 4MB of processes, the system crashed. One of my distributors told me that they did a similar test with no ram disk and the system crashed when they went above 16MB of processes/kernel. So while the system said it saw more than 16MB, it appears that it did not use it correctly. -- Conor P. Cahill (703)430-9247 Virtual Technologies, Inc. uunet!virtech!cpcahil 46030 Manekin Plaza, Suite 160 Sterling, VA 22170
urban@cbnewsl.att.com (john.urban) (05/13/91)
In article <1991May13.004012.18572@pegasus.com> richard@pegasus.com (Richard Foulk) writes: DELETED STUFF > I've seen people >reporting 24 megs and more, in this forum, on ISA bus machines. > >So what is the real situation today? Which 386 ports of Unix will support >greater than 16 megs on the ISA bus? (Did the MEMRANGE spec actually >vaporize with ISC's 2.2, or is it just hiding somewhere else?) AT&T UNIX System V/386 Release 3.2 Version 2.2 (and higher, ie 3.2 2.3 and 4.0) support greater than 16 Meg on the ISA bus. When more than 16 meg is available it "moves" the DMA which would of occured above 16 meg to below 16 meg so that the ISA bus (DMA chip) can do the DMA successfully. Sincerely, John Ben Urban att!garage!jbu
scf@statware.UUCP ( Steve Fullerton) (05/14/91)
In article <1991May13.115029.14295@virtech.uucp> cpcahil@virtech.uucp (Conor P. Cahill) writes: >richard@pegasus.com (Richard Foulk) writes: >>... >As far as I know, SCO is the only vendor to support > 16 MB (although I >don't know if it will work on ISA bus systems, but I think it will). SCO >did this by using the "epanded memory" trick that is used by many dos >systems (it copies a page down below 16MB whenever a page is accessed >by a bus operation). This works the same way under EISA systems, even >though it isn't necessary there. We are running SCO UNIX 3.2V2 on an ISA system with 32 MB of memory and haven't had many problems. We run X (from ODT) with TCP/IP, NFS, and Ingres with additional swap on a second disk (2 760 MB ESDI). The boot message is mem: total = 32384k, kernel = 5740k, user = 26644k The average number of processes hovers around 120 with only 5-6 users (lot's of X though). The only memory related problem is that we seem to have maxed out some of the kernel parameters; e.g., NREGION. We get "region table overflow" messages, but trying to push it up with configure warns us that the maximum is 350 and exceeding it will result in SEVERE system problems. -- Steve Fullerton Statware, Inc. scf%statware.uucp@cs.orst.edu 260 SW Madison Ave, Suite 109 orstcs!statware!scf Corvallis, OR 97333 503/753-5382
randy@chinet.chi.il.us (Randy Suess) (05/14/91)
In article <1991May13.115029.14295@virtech.uucp> cpcahil@virtech.uucp (Conor P. Cahill) writes: >As far as I know, SCO is the only vendor to support > 16 MB (although I >don't know if it will work on ISA bus systems, but I think it will). SCO > Sterling, VA 22170 AT&T SysvR3.2? runs on their 6386 box's (ISA) with up to 40 megs memory just fine. They use their own DMA controller on a 32 bit bus. I guess the kernel must have special support for over 16 megs, because when I try to run QEMM (a 386 memory manager) under dos on the same machine, it goes nuts. Bring it down to 16 megs, and everything runs fine. -- Randy Suess randy@chinet.chi.il.us