• Please review our updated Terms and Rules here

Recent content by Svenska

  1. S

    Need some help from 6809 programmers at byte level

    In an optimizing pass, the assembler may change a long jump into a short jump to save a byte. This causes addresses further down to shift and may enable/disable further optimizations (aligned tables may move around, additional padding may happen, short jumps may no longer reach, long jumps...
  2. S

    Best Sound Card Clone for 286

    On my 286/12, I had some stability issues with an SB16 (CT4170), even though UNISOUND did a great job initializing it. I had better luck with a MAD16 Pro (OPTi 82C929A with OPL3 clone): Excellent sound quality, good SB Pro compatibility and WSS support. Feels a bit like overkill for a 286, so...
  3. S

    ed tutorial

    There are a few well-known data structures designed for editor uses, such as gap buffers, ropes or piece tables. But the on-disk format of a text file is always linear without gaps, so your options are quite limited. In CP/M, inserting text and saving will always require rewriting the remainder...
  4. S

    Need some help from 6809 programmers at byte level

    Old versions of MASM for x86 assumed the long form in the first pass, and would generate the short form (plus a NOP as padding) when possible. If the programmer specified the short form, it would always be generated (or an out-of-range error). Introducing additional passes to optimize can lead...
  5. S

    CPM BIOS, BDOS, CCP layout on Disk vs RAM

    Because the system tracks (often 0+1, but that depends on the disk format) may be too small to contain the final memory image, some implementations use a CCP.SYS (or some other file) which replaces the booted CP/M with a more advanced version (for example, a larger BIOS with additional disk...
  6. S

    Sun386i. Overdrive processors: Why don't they work?

    Unfortunately, I don't know enough about these systems for really good answers. The firmware is most likely memory-mapped permanently, so you should be able to read it somehow. Obviously, removing the ROM chips and reading them externally would also work. The firmware appears to be similar to...
  7. S

    Sun386i. Overdrive processors: Why don't they work?

    While there is no CPUID, the BIOS can identify the CPU. It is possible that the Sun firmware checks the CPU ID early and aborts. But when the system was designed, the Cx486 chips did not exist yet. It's also possible that the firmware simply crashes because the CPU behaves differently. With the...
  8. S

    Anyone ever though about a clone/improvement on those RAM-drives?

    Correct. Which is why I wrote "most". I'm not aware of any affordable SCSI-to-SD solution using such a high-performance controller. A BlueSCSI is said to achieve approximately 3 MB/s when imaging a fast disk by itself (acting as the host controller). Personally, I've only used SD cards in SPI...
  9. S

    Anyone ever though about a clone/improvement on those RAM-drives?

    There is no point, none whatsoever. The iRAM was very expensive, too small and speed-limited by its interface. Alternative A: Any reasonably modern SSD will be able to saturate the interface. More capacity, same speed, cheaper. Alternative B: Add more RAM and configure it as a RAM drive. Same...
  10. S

    Xenix External Added Hard Disk Shutdown

    The posted shutdown script unmounts /dev/hd1a. It does so in line 66 (when it does single-user), and in line 93 (when it halts). This script will never run mount or fsck. It also does not need any modification. It would be helpful to know why unmounting this device fails. I'd assume that there...
  11. S

    Emulated parallel printer

    It definitely is, but the displays are relatively small get expensive easily. Price tags are cheap but not good enough. Most displays need to be refreshed continuously, even if the content doesn't change. Only intelligent displays with an integrated framebuffer (or eInk type) can be updated at...
  12. S

    Emulated parallel printer

    Interfacing to the parallel port, connecting an SD card and rendering into an image file are easy. But you can't drive a high-resolution display with an Atmega328 to show the printed output (many ESC/P2 printers support 360 dpi). That's the problem.
  13. S

    Emulated parallel printer

    I took a look at Crystalfontz. Their graphical OLEDs and LCDs max out at 320x240 resolution, so that's no good for printer emulation. But they are easy to interface to; I've used old Nokia displays in the past and they were nice. Higher resolutions are only available through TFTs, which either...
  14. S

    Emulated parallel printer

    Do you have a good source for it? How expensive is it? Does it have decent documentation? What type of interface does it use, does it need permanent refreshing and how much bandwidth is needed to display a static image? (= Do I need special hardware to drive it, can I use an el-cheapo...
  15. S

    Not Enough Memory Question

    You still need the "DOS=HIGH,UMB". Sorry, I forgot that when I rearranged your file. The shell, buffers, files, fcbs, stacks and lastdrive values are set to sensible default values if they missing. The only setting I ever had to change myself was LASTDRIVE, when I had a CD-ROM and multiple...
Back
Top