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apersson850

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About apersson850

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  1. Yes, I referred to the original Extended BASIC cartrdige. And it's correct that TI marketed it with the 36 K ROM size back then.
  2. Your math is a bit off, though. In spite of the ROM being 12 K, not 16, 12+24 is actually 36 K. That's the amount of memory Extended BASIC added.
  3. Hardly, since it has been introduced with later accessories. Which is what I meant with my comment above. The UCSD p-system was the only to include a date stamp from the beginning. The other things mentioned have been added by third party accessories introduced later. But it's good they've settled on using the same format!
  4. It doesn't help here, but the only system I know of for the TI, that does include at least a date stamp for the files, is the UCSD p-system.
  5. I didn't know there were such programs around. I wrote my own back in the 1980's. Same idea. But there were no RAMdisks around at that time, so I abandoned the project, as I thought processing time became too long when the number of disks included became large. But apart from that, it was a similar idea as with Diskodex.
  6. Yes, obviously. I've not studied the GPL interpreter in any kind of detail. But the p-code interpreter needs 6-7 instructions to figure out what to do. If the job then can be done with one instruction, it's 7-8 instructions instead of one. Like adding what's on top of stack with the second word on the stack, leaving the result on the stack, can be accomplished with the A *SP+,*SP instruction on the TMS 9900. For more complex instructions, the overhead is of course less, relatively spoken.
  7. It has been mentioned that they at least considered making a microcontroller which executed GPL directly.
  8. Then we have the p-code card, which in addition to having 12 K ROM (in the DSR space, >4000 - >5FFF, where the top 4 K is paged by CRU bit >1F80) also has 8 GROMS. These all have 6 K memory, but the GROM base is also inside the DSR space. Thus it's right in the ROM space, but it's fully decoded, so it only occupies the words it really uses. The code in the ROM simply jump over these addresses. Thus a total of 60 Kbytes of memory on that card. Since this is completely separate from console GROM space, it's not limited to the five top GROMs here.
  9. ROM on a cartridge is at >6000 - >7FFF. All "special" things are mapped to ports in the >8000 - >9FFF area. That includes console RAM, video, sound, speech and GROM access. It doesn't matter if the GROMs are in the console or in a cartridge. They have the same access port. Since you can have a maximum of 8 GROM on a single port, this means that the cartridges can't have more than 5, as the console has 3. It's not only the GPL interpreter that lives in >0000 - >1FFF space. There is also floating point routines, cassette DSR, interrupt handling, startup code and some other support. It's not like 8 K is available. But more than half should be, yes. Indeed I have a mechanism which allows RAM over the entire address range in my console. By default, only the normal 32 K RAM is accessible, but using CRU bits, I can enable RAM in any of the other four 8 K banks too. Or release the standard 32 K RAM, so that a normal RAM expansion in the box shows up instead. This gives me access to 64 K RAM in the console alone, and 96 K RAM if the memory expansion is present. Did any 8 K GROM exist at all? Devices like the GRAM kracker and Maximem didn't use GRAM chips, but ordinary memory and just simulated GROM with some extra logic around them.
  10. Yes, you're right. I had forgotten about the difference between TIM 9904 and 9904A. But again, it shows the futility of comparing crystal frequencies once again, as the output of the two is the same.
  11. Still, one interpretation of another interpretation makes two of them...
  12. The TMS 9900 was also used in the TI 990/5 version. By Texas Intruments, that is. There were of course external users of these processors in other products. The TMS 9900 was running at 3 MHz in the 99/4A. It's a bit misleading to distinguishing the clock frequency of the 9995 as 12/3 MHz, since it give the impression that it operates at the same speed internally as the 9900. It doesn't, it's 2-3 times faster. If you only look at the crystal, connected to the TIM 9904 clock generator for the TMS 9900, that was a 48 MHz one.
  13. My largest program for the TI 99/4A is a bit over 4000 source lines. But that's written in UCSD Pascal. A friend, Sven Lundgren, tried to implement it in Extended BASIC first, but eventually gave up. I found Pascal to be a better environment to use, so I did finish it in that way instead. The program uses quite a lot of overlays, where different functions (data entry, result display, printout, disk storage of data etc.) are in different modules, which are loaded into memory on demand. It's of course pretty easy to make a program which uses all memory, if it also handles a substantial amount of data. Especially if the data can grow unlimited, like with a word processor. The word processor me and Lennart Thelander wrote in Extended BASIC with assembly support used all 48 K RAM and used overlays to load the program from cassette. These were created when there were no RAMdisks or other memory expansion, outside of the standard 32 K RAM, available.
  14. The index hole sensor was my immediate thought, when I read the first post. Then I continued reading and saw that you already figured it out. But perhaps not why this is the first thing to check? The index hole is normally used only for formatting. It's to tell the drive when one turn has been completed, so that it knows where to start the track, and sometimes confirm the whole track got written before it ended. It will also align the tracks with each other. But once formatted, the drive and controller uses the magnetic information on the disk to figure out where the tracks are, for read as well as write operations. The index hole isn't needed then. Note that this is for soft sectored disks, the kind our TI uses. Hard sectored disks existed, with one hole for each sector around the disk, and an extra hole at the starting point.
  15. Exactly what I did. Two cables, one for two internal drives, another for the two external drives. That's very special in my case, since I have the exernal drives in a separate box, so the external ribbon cable goes to a connector on the outside of that box. Then from the inside to the two drives.
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