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About Casey

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  1. It's definitely interesting to see from this document how 99/4 TI BASIC came to be, and then what was added to make Extended BASIC, and then what went into the 99/8's Extended BASIC II - each a superset of the previous, but each very much defined by this standard. Equally interesting is what was defined by the standard but not used in any of the Home Computer BASICs. Some make sense (the keyed file stuff that was used on the 990) but the values returned by CALL ERR I found interesting. Extended BASIC gives only a passing definition of the error severity ("this value is always 9") but the standard had several possible values for this. Thanks *very much* for sharing this with us!
  2. I believe that comes (among other possibly places) from the Apple DOS 3.3 manual. I know it says that in there. Apple's manuals were rather witty back then.
  3. If one were to get an Ultimate 64 and a new C64c case - where does one obtain a keyboard? I saw someone was working on a new drop in keyboard replacement but it look like that effort stalled. Are people taking keyboards from old/dead 64s?
  4. If it's an actual CP/M boot disk image, after you mount it in the SD2IEC, you'll have to use this command: BOOT,D0,U9
  5. I was going to say something similar. You should be able to create a .d64 or .d81 and format it within CP/M. I was able to play with CP/M on Vice using a .d81 boot disk image. Those can be found I think pretty easily and I would think it would work. OLD CS1 has given me something to try this weekend though. I’m curious also if you can insert a MFM disk image into the emulated 1571 in Vice and see if CP/M can access it.
  6. If I remember right (from years ago) - the CP/M system disk is a flippy disk - not a double sided disk (i.e. you turn it over to use the back side). It should boot in a 1541 but it certainly would not be fast. The 1541 can’t use any of the MFM formatted CP/M disks that the 1571 can read however. May or may not be an issue in your case. I think to make a system disk, you use the FORMAT.COM utility in CP/M to format the disk first, and then you just need to PIP the CPM+.SYS and CCP.COM to the new disk and it will be bootable. Some good information here: https://www.commodore.ca/manuals/128_system_guide/sect-11.htm#11.4.1
  7. They do. CALL -151 from either BASIC will drop you into the monitor.
  8. I ordered a bunch of cassette tapes to use with my TI 99/4A from Amazon pretty cheaply I think. I think it came in a pack of about 20 tapes. So if you can’t find something locally, it’s a good option. There are some reasons a person may need/want to use tape. Not sure how it is with the VIC 20, but several of the very earliest TI games have a game save feature that only will read/write to tape, even if you have a disk drive or something more modern attached to the system. (Video Chess is one of these). I could see the VIC having some like this also, since most software was on cartridge or cassette.
  9. Generally, it does not matter if the computer is on when you insert a cartridge. The cartridges will almost (but not always) cause the computer to automatically reset to the title screen when you plug it in. There are a couple of exceptions. Mini Memory is a battery backed cartridge that contains some RAM that you can store programs in. It definitely does not like to have the computer on when you plug it in. I also would not do that with a FinalGROM99 cartridge if you get one, since it has a rewriteable ROM in it. Better to be safe than sorry. Most of the manuals also tell you to remove the cartridge while the computer is on, after returning to the title screen. My experience is that sometimes works ok, but sometimes locks the computer up. All that being said, I have never damaged a console or a cartridge by removing it or inserting it while the computer is on. Take that with a grain of salt.
  10. If you are going to be a BASIC programmer, hands down, the CoCo has a much better version of BASIC than the VIC 20. The CoCo's BASIC has commands that support sound, color, and graphics that the VIC's BASIC just doesn't have. If you are going to mainly play games, the VIC probably has the better library of games than the CoCo. The 22-column VIC display is a bit more irritating to me than the 32-column CoCo display, but the green background of the CoCo is more irritating than the VIC.
  11. I realize this thread is about the Atari 400, but the TI 99/4A has cursor movement keys for editing typos. It doesn't use a full screen editor like the Atari or Commodore computers do, but it has a line editor and by using various key combinations you can move around in the line, insert characters, delete characters, etc.
  12. For years (at least into the mid 90s), Iowa State University’s College of Engineering’s career office used a TI 99/4A hooked up to a black and white TV as a display showing which companies were coming to interview for jobs and when.
  13. Didn't the 3K expander fit in the memory hole before the 5K that came with computer in the memory map? If the built in RAM was bad, would the computer not start at all with the 3K expander? Or could it possibly start BASIC and show less than 6656 bytes free if the memory test got up to the bad memory? (Just curious)
  14. Yep, I just tried it. Reading DS in BASIC 4.0 affects ST, so the updated version saving it off would work. Some of the dual drives (I think the 8250) also return the drive number where the error occurred. It may not be necessary to retrieve the drive number, but it is there if you need/want it, so I just included it in my example. And you are right. The disk I think only uses 0 and 64 for ST. Cassette has several other values for ST also (64 being end of file as well)
  15. Oh! One other thing I forgot. Any I/O command can cause ST to change, even if you don’t expect it would. That can cause you problems you don’t expect to occur. A common workaround for this is: 100 OPEN 8,8,8,”0:LEVEL1,S,R” 110 INPUT#1,A$:SS=ST 120 PRINT A$ 130 IF SS<>64 THEN 110 140 CLOSE 8 This assures that you know the value of ST right after you do your INPUT and don’t lose it somehow by something else. What I suspect, though I haven’t tried it yet, but the check of DS/DS$ or the INPUT#15 method to read the disk error channel may change the value of ST to 64 after you read the error status (it’s 1 record, and the last one the disk will give you - that might set ST to 64 at that point). I may play with that this afternoon, but that would explain why your program only reads 1 line from the file. The error check may set ST to 64 right after that.
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