An interesting thing happened a few weeks ago that might be related to your research. I have a dedicated server for the task of running a specific DOS database application. Everyone who uses this application uses it through DOSEMU. As my number of users increased, I found that a shared mem setting was limiting my number of users to 32 sessions. In order to buy myself some time to find the solution, I tried to let some users run the application using their own CPU's and attaching to the Linux server w/ SAMBA. It was unusable because every time the application tried to access a record, it would give a message, "Waiting for lock" and constantly wait. I don't think I ever successfully used that configuration. While using DOSEMU (on lredir drive) I have NEVER seen that message, and have not experienced any kind of corruption. This program is the primary application used by > 75% of our employees. We always have 30-45 sessions going. Each and every user uses exactly the same configuration once into dos. Maybe that is why we have not experienced any problems. We have been successfully using our current configuration, without problem, for 10 months now, so if there were a problem, I'm sure we would have seen it by now. If there is any data I can give you about our configuration or usage that will help your research, let me know, I'm happy to aid the cause. Matthew Nuzum [EMAIL PROTECTED] wrote: > I suppose there is still a problem with DOS-like file sharing > in at least three: DosEmu, Samba, Mars. The problem is: > > assume have tasks of two types accessing some file: > - task type A opens a file Read-Only Deny-Write > - task type B opens the file Read-Write Deny-None > > DOS file sharing rules allow any number of tasks type A to run > simultaneously, or any number of tasks type B, but forbid to > run tasks of different types simultaneously (because type A > denies writing to others, and type B wants writing) > > but file sharing rules in DosEmu or Samba (I am not sure about > Mars, but Mars does it in a way I would discourage - it creates > files in its own directory to tell about file sharing) allow > tasks type A and B to run simultaneously because they both use > the same area lock: read lock for byte 0x7fffffff of the file. > > This means if an application may try these two access types on > the same file, it is likely to cause problems. So I am working > on a fix, and my knowledge about it is on page: > ftp://zfja-gate.fuw.edu.pl/mail-ftp/zfja-ftp/linux/index.html > Click "mars fixes info" for description of my ideas of fixing it. > > Jerzy Tarasiuk
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