Search found 308 matches

by janbredenbeek
Wed Apr 24, 2019 4:24 pm
Forum: Software & Programming
Topic: SCREEN1 = SYSVAR @ JSROM
Replies: 6
Views: 162

Re: SCREEN1 = SYSVAR @ JSROM

Typical non-Minerva applications that make use of the second screen need do the following: ⋅ Allocate any needed memory from the system ⋅ Go into supervisor mode and never leave it again while the second screen is in use. Note that implies that your program will take over the ma...
by janbredenbeek
Wed Apr 24, 2019 4:21 pm
Forum: Software & Programming
Topic: SCREEN1 = SYSVAR @ JSROM
Replies: 6
Views: 162

Re: SCREEN1 = SYSVAR @ JSROM

Bottom half seems almost writable by a program, I wish to decompose the rest. At the top I can most likely see system variables, there comes somewhere superbasic area, QDOS stack. I wonder what is that piano keyaboard pattern, that looks very regular? The thin lines are the slave block table (8-byt...
by janbredenbeek
Tue Apr 23, 2019 11:45 am
Forum: Software & Programming
Topic: How to reliably detect USER or SUPERVISOR mode across CPUs
Replies: 8
Views: 231

Re: How to reliably detect USER or SUPERVISOR mode across CPUs

Defining your own traps is fine for jobs, but would that be a good idea for a global device driver? Probably not, but that wasn't mentioned in the original post. Speaking of which, I recently discovered such a thing in the SD card driver for the Q68 supplied with Minerva. It was a TRAP #14 in the r...
by janbredenbeek
Mon Apr 22, 2019 11:44 pm
Forum: Software & Programming
Topic: How to reliably detect USER or SUPERVISOR mode across CPUs
Replies: 8
Views: 231

Re: How to reliably detect USER or SUPERVISOR mode across CPUs

Darn it - I thought I had researched thoroughly :-) So, what does it mean I wonder when the Guide states 'Therefore, all reads of the status register are emulated.' Does this mean that MOVE SR, <ea> can be used and, if it does cause an exception due to running on a later processor, that SMSQE will ...
by janbredenbeek
Sun Apr 21, 2019 11:30 pm
Forum: The Off-Topic Section
Topic: Today I Received...
Replies: 42
Views: 3661

Re: Today I Received...

I’m working at editing the 6850 driver I believe you wrote to work with a 68681-similar device. It’s tough going but I am making progress. I don’t suppose you have a commented copy of it? :D I don't know which version you have, but I believe the source on GitHub is reasonably well commented? https:...
by janbredenbeek
Sun Apr 21, 2019 12:46 am
Forum: The Off-Topic Section
Topic: Today I Received...
Replies: 42
Views: 3661

Re: Today I Received...

I also had one of the very first USRobotics HST modems in 1987? It got destroyed by lightning in 1989 or 1990. I just googled it and they still sell a model in the exact same style, but supports 56K - I think mine topped out at 9,600 HST. I bought my first USRobotics in 1990, this was a 14400 HST m...
by janbredenbeek
Thu Apr 18, 2019 11:00 pm
Forum: Software & Programming
Topic: Let's chat about: Filing Systems!
Replies: 3
Views: 220

Re: Let's chat about: Filing Systems!

This is an enquiry about the current state of play with the filing system on the QL, and the realistic or unrealistic prospects for an improved FS. One of the issues with Qdos is it uses a block filing system. As the system grows beyond anything Sinclair imagined in 1983, the blocks consume more an...
by janbredenbeek
Tue Apr 16, 2019 4:12 pm
Forum: Hardware
Topic: Optimal Flatscreen monitors for QL and Q68
Replies: 24
Views: 745

Re: Optimal Flatscreen monitors for QL and Q68

Hi Peter, I still don't quite understand what you mean. In the QL modes, the Q68 creates rectangular "QL pixels" that are 2x3 screen pixels, so the complete 4:3 flatscreen area is used. I assume most CRT monitors used with the QL were also 4:3 in geometry - and the picture also filled the ...
by janbredenbeek
Tue Apr 16, 2019 9:04 am
Forum: General QL Chat
Topic: What makes the OS for QL any better, different, unique ?
Replies: 6
Views: 183

Re: What makes the OS for QL any better, different, unique ?

Pr0f wrote:Would we have had Linux without the QL ?

Maybe not, since Linus Torvalds has written programs on the QL, including an assembler and editor (according to Wikipedia). I wonder if they're still around somewhere.

Jan.
by janbredenbeek
Mon Apr 15, 2019 3:37 pm
Forum: Hardware
Topic: Optimal Flatscreen monitors for QL and Q68
Replies: 24
Views: 745

Re: Optimal Flatscreen monitors for QL and Q68

If the aspect ratio was indeed 4:3, the resolution would be 512x384, not 512x256. I meant the actual screen aspect ratio, not pixel shape. Most CRT screens were about 4:3, and that determined the historic QL look - which the Q68 reproduces in the QL modes. QL pixels were knowingly designed non-rect...