Hardware incompatibilities
Posted: Fri Jan 14, 2011 8:25 pm
I was surprised today when trying to sort out a working disk system for a QL customer, by some of the apparent incompatibilities between QL hardware.
Technology Research Limited disk interface (this has a built in parallel port as well as a disk interface - I did not get around to seeing if it had memory or not).
This was tested with toolkit II EPROMs with the following (surprising) results:
- 2 x Toolkit II EPROMs were not identified and could not be used.
- 1 x Toolkit II EPROM was recognised, but then the TRL disk interface was not linked in.
Very odd - I guess the reason between the three results was more down to the link code in the TK2 eprom - this might have changed over the different versions, so that instead of the Toolkit II EPROM being installed last, it was installed first.
It did not work with a 512K expanderam, so presumably has some memory built in.
PCML Q+Disk Interface
I have 3 of these - one of which does not work with disks (needs a new WD1770 controller probably), so I did not try it.
The other two interfaces appear to have 256K and 128K built in respectively.
Both work with Toolkit II.
However, when plugged into 256K Expanderam, the QL goes through the memory check pattern and then displays a white screen suggesting a RAM issue (maybe a timing issue?)
Technology Research Limited disk interface (this has a built in parallel port as well as a disk interface - I did not get around to seeing if it had memory or not).
This was tested with toolkit II EPROMs with the following (surprising) results:
- 2 x Toolkit II EPROMs were not identified and could not be used.
- 1 x Toolkit II EPROM was recognised, but then the TRL disk interface was not linked in.
Very odd - I guess the reason between the three results was more down to the link code in the TK2 eprom - this might have changed over the different versions, so that instead of the Toolkit II EPROM being installed last, it was installed first.
It did not work with a 512K expanderam, so presumably has some memory built in.
PCML Q+Disk Interface
I have 3 of these - one of which does not work with disks (needs a new WD1770 controller probably), so I did not try it.
The other two interfaces appear to have 256K and 128K built in respectively.
Both work with Toolkit II.
However, when plugged into 256K Expanderam, the QL goes through the memory check pattern and then displays a white screen suggesting a RAM issue (maybe a timing issue?)