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kelli217

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Posts posted by kelli217

  1. I have a vague memory of there being a discussion somewhere about the FAT32 filesystem being more friendly to file seeks. I don't know whether the ability to do it has been implemented in the DOS part of the kernal, or if not, whether it's planned to be. In any case, with r41 it's only going to work with the SD card image, because that's the only well-supported storage device on the emulator. The host file system is basically a highly simplified load/save only interface.

  2. On 11/21/2022 at 2:21 PM, idea1407a said:

    CP/M was created by DEC, https://en.wikipedia.org/wiki/Digital_Equipment_Corporation. I understand it was a business operating system. Many 8 bit computers did not run CP/M until they were big enough. But the Commodore 64 had a CP/M cartridge and the C128 came with CP/M inside it, if memory serves, unless that too was a cartridge, but I had a C128 and I don't remember buying it separate. As far as I know the ZX Specturm 48K didn't have CP/M but I just learned that the Spectrum +3 did. 

    CP/M was not created by Digital Equipment Corporation, but by Digital Research, Inc.

    Just like the 65C02 is not a product of Western Digital, but Western Design Center.

    And WordStar was not from Microsoft, but from MicroPro.

    Apparently it's a thing to reuse elements of other companies' names—like Business Machines, whether they be International or Commodore. 🙂 

    • Like 2
  3. On 11/10/2022 at 3:59 PM, rje said:

    I wonder if a Classic-II style bus would work with a 6502-based project?

    I couldn't say. I know there are some old 6502 board designs for the S-100 bus. But I don't know how the Classic-II bus compares to the S-100 bus.

  4. On 11/10/2022 at 4:24 PM, neutrino said:

    @kelli217 Cars are way more than computers a victim of entropy ie wear. So eventually there will be no old car that can be used for parts nor any new-old-stock. And so people might still desire the car or other retro object. And will have to fabricate them using the old drawings or (3D) precision measurements.

    What will remain is the blue prints ie the information about the car. All else will decay.

    ok

  5. On 11/8/2022 at 5:50 PM, neutrino said:

    What would hinder a replication?

    Remember what I initially said: A classic car that you could recreate completely from scratch, from the frame up, using third-party replacement parts. That precludes there being an existing car to use for parts, or any new-old-stock or other OEM parts. It also precludes fabricating any parts yourself.

  6. Okay... here's the tricky part.

    There was only one model of Commodore computer that would let you have uppercase, lowercase, and a full set of graphics characters on screen at the same time without resorting to special modes of the graphic system. And that was the 128. And it would only do it on the VDC screen, not the VIC screen.

    The X16 can do it too, but it requires the aforementioned special modes. You have to set layer 0 and layer 1 to text mode, and put one of them in uppercase/graphics mode, and the other in lowercase/uppercase mode. And then you have to be careful not to overwrite one layer's character cell with a character in the other layer. (I mean, unless you want to. Just like you had to be careful back in the days of film cameras with manual winding not to expose the same frame of film twice, unless that was what you were deliberately trying to do.)

    • Like 1
  7. In theory, if you were to have a UV emitting LED that didn't have any visible light output, it would only be detectable when striking objects that fluoresce under UV illumination. In practice, of course, there's almost always a little bit of parasitic visible light. 😛 

    • Like 1
  8. Yeah, there are a lot of (x)xx50 and (x)xx51 possibilities to put on an expansion card. We had a big discussion about whether or not the 6551 (specifically the 65C51) was a good choice. Apparently some of the more recent fab runs may have a problem with the TDRE flag, which was a bit particular even when working properly and required a delay.

  9. The frame rate on most e-ink displays doesn't usually require the sort of high-bandwidth connection found in such standards as HDMI. There are several SPI and I2C e-ink displays available on the parts market.

  10. Psst. More traces on the motherboard = more interference, more capacitance, and more cost to manufacture.

    And a 6502 only has 16 address lines. The banking system we've got supports as many as 256 chunks of 8K of RAM that can be switched. If you add more pages, how are they going to be chosen? If you make the page bigger, that interferes with the size of either the ROM above it, or causes the I/O to be pushed down lower (and the non-banked RAM also gets smaller).

    Why would you want to completely redesign the entire system this way, and why would you think that the design team hadn't already given this thorough consideration before coming to the decision to do things the way they're being done?

    • Like 1
  11. On 10/20/2022 at 12:53 PM, BruceMcF said:

    I was under the impression that there is a timer in the FM chip and a timer in the RTC chip. Maybe one or both of those can generate an IRQ interrupt rather than an NMI, so you would wrap the Kernel VBlank ISR routine with a routine that returns to poll for your timer IRQ having happened while the VBlank interrupt was being serviced.

    Doesn't the RTC chip come in on the same I2C connection as the PS/2 connectors? Well, at least, routed through the same microcontroller. My money would be on the FM chip as being slightly more likely to support being able to generate/trigger an IRQ instead of an NMI.

  12. That it's possible given the then-current slot specification to build an expansion card that could probably get the 65C02 to pause long enough to do DMA. But you'd have to 'be nice' and not hold the bus for too long or other things could start to be a problem, like VIA, I2C for keyboard and mouse, VERA, YM2151... and there's no intention of including any DMA in the system as it is.

    Bluntly, neutrino, you're coming WAY late to the party, and offering up ideas and suggestions that are not going to get included because the system is in the final stages of development before manufacture. Things are not likely to change at this point in any major architectural ways. Even the removal of the second 6522 from the motherboard is not going to represent that much of a change in the way the system operates, but will only take away one of the 32-byte I/O channels (and free it up as an I/O channel for other uses) and require some addresses in the KERNAL to be revised.

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