Common system-wide problems

The following list summarizes

some of the more common system-wide problems that can happen:

• 
  
  
  Systems running graphical terminals or many different networking protocols often need to have the value of STREAMS tunables adjusted. Exceeding STREAMS resources generates error messages on the console and in the /usr/adm/message file, and may cause graphical screens to be corrupted or networking operations to fail. This can cause a number of odd conditions such as random vertical lines on the graphical display. If you have intermittent odd problems on the system, use the
  netstat(TC)
  -m command or the strstat function in crash(ADM) to see if there have been overflows for any STREAMS resources.
  

• 
  
  If files from system A are NFS-mounted on system B and system A is stopped, System B may be virtually non-functional. This is especially true if several processes on system B are trying to access the NFS-mounted files; most system resources will be dedicated to attempts to access the missing files and log their failures. Unmounting the NFS filesystems or rebooting system A will resolve the problem. In most cases, it is not necessary to reboot system B.

• Unless you are testing new drivers on your system,
  
  
  a large number of obscure kernel messages on the console and in the /usr/adm/messages file that seem unrelated to any executing process may indicate a hardware failure on a key system component such as a memory board or the disk on which the root filesystem is located.

• 
  
  If you are using memory-mapped peripherals that work well with DOS but behave erratically with your SCO system, try reinstalling the device and driver very generically. In other words, put the VGA card in an 8-bit slot; turn off RAM caching, disk caching, and shadow RAM; use 1 wait state, and ATCLK(* Mhz) on the card bus. Any cards that need to be software configured (such as the wd8003e or 3c503) should be checked in DOS. Move any shared IRQs to non-shared positions and do not use IRQ2 if you can avoid it. Check that port addresses overlap, and remember that intelligent memory mapped serial cards
  
  cannot have their memory maps cached.

  When the device is installed generically, it should work. You can then put back the special features, one at a time, until you determine which one is causing the problem.