Home
Support

Knowledge Base

BSPs and drivers
Community resources
Product documentation
Questions?
Contact us

maximum IFS size on x86
 
________________________________________________________________________

Applicable Environment
________________________________________________________________________
  • Topic: Maximum IFS size on x86
  • SDP: 6.6.0, 6.5.0
  • Target: x86
________________________________________________________________________

Issue
________________________________________________________________________

IFS up to a certain size show random errors on x86 hardware with BIOS. How do I resolve this?

________________________________________________________________________

Recommendation
________________________________________________________________________

The limit for the fsq6 loader is about 14MB (24-bit linear address minus the potential 15-16M ISA/ROM hole minus the starting address of the loaded copy at 1M).

The problem is in the startup code, which will copy itself to where it was linked, which by default is 4M. It does this regardless of the boot loader (diskpc2 or diskpc2-fsq6).

So if your boot image is >3M, then when it is loaded at 1M startup copies about 128k of itself to 4MB, overwriting some of the image (you can see this in the 'corruption', the first bad bytes are the startup signature 0x00ff7eeb; also why the corruption seems random based on how they layout their boot image).

Possible workarounds:
* keep image size <3M
* change where you link the image - in the boot file add an attribute, say "[image=8m]" (just prior to the "[virtual=..]
boot ... " line) to link the startup to eg 8M, which would allow you a 7MB boot image.

________________________________________________________________________
NOTE: This entry has been validated against the SDP version listed above. Use caution when considering this advice for any other SDP version. For supported releases, please reach out to QNX Technical Support if you have any questions/concerns.
________________________________________________________________________


Related Attachments
 None Found





Please contact us with your questions or concerns.