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22 votes

Are BIOS ROMs interchangeable among different vendor's PCs?

No reason to expect it works at all. So if the CPU can even start executing the code, the moment where it goes wrong is when there are instructions for a newer CPU, or some chipset-specific ...
Justme's user avatar
  • 33.9k
22 votes

When did wear leveling in flash storage come up?

It's a long-standing and well understood design principle. The very first EEPROM I designed into a system in about 1989 had wear levelling implemented in the software. It was a simple conclusion that ...
TonyM's user avatar
  • 4,266
20 votes
Accepted

Are BIOS ROMs interchangeable among different vendor's PCs?

How interchangeable was PC BIOS? Usually not interchangeable at all. Keep in mind, there is no single PC-BIOS, but a machine BIOS. Different CPUs, chips sets and additional hardware need specific ...
Raffzahn's user avatar
  • 226k
16 votes

When did wear leveling in flash storage come up?

It was certainly a known practice in 1993 when I designed a filesystem for EdenOs that had an optional wear-levelling layer for flash-based storage (battery-backed RAM on PCMCIA was the favourite ...
Frog's user avatar
  • 1,385
14 votes
Accepted

What is this code on the zero page that was put there by the BASIC ROM?

It's part of the BASIC interpreter loop. It reads one byte of the tokenized BASIC program, setting zero flag if it's a colon or a zero byte and clearing the carry if it's a number. You can see it used ...
9 votes

When did wear leveling in flash storage come up?

Wear levelling is/was originally a feature of file systems. FLASH 'drives' were at first not made to emulate existing standards. In fact, they were not 'drives' at all but just the flash memory chips ...
Raffzahn's user avatar
  • 226k
7 votes

What is this code on the zero page that was put there by the BASIC ROM?

In addition to the Community Wiki answer: This routine with entries CHRGET and CHRGOT is not only part of the interpreter loop, it used in every statement and function which has to "parse" further ...
Johann Klasek's user avatar
7 votes

Which generations of PowerPC did Windows NT 4 run on?

In general, NT3.51 for PowerPC should run on all PReP machines (Specs) from IBM or Motorola (*1), as long as it features an ARC bootloader - that's why it won't come up on CHRP PowerPC Macs with Open ...
Raffzahn's user avatar
  • 226k
6 votes

When did wear leveling in flash storage come up?

While most flash memories use a different circuit topology from most EEPROMs (some devices using the EEPROM circuit topology are marketed as flash, and perhaps vice versa), many EEPROM memories have ...
supercat's user avatar
  • 37.3k
6 votes

When did wear leveling in flash storage come up?

Basic static wear leveling is ancient by technology standards. Simple implementations were used somewhat regularly with EEPROMs at least as early as the mid 1980's, and probably earlier even than that....
Austin Hemmelgarn's user avatar
6 votes
Accepted

Trying to create a filesystem ROM for Amstrad CPC but tape is still waiting

As I was expecting, it was an error in my code :) pelrun was very kind and found the bug (see my question on CPCWiki's forum) so props to him. I'll try to explain the issue: Notice I'm hooking into ...
kaoD's user avatar
  • 251
5 votes

How exactly does the Apple II monitor set and use the "last opened" and "next changable" locations?

The model of how the Monitor command line works in the Apple II Reference Manual, and most other documentation, isn't really in line with how it does work. It doesn't help that the Monitor itself, at ...
cjs's user avatar
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4 votes
Accepted

Change text color in Z80 assembly for Amstrad CPC 464

Maybe start with the Text Output routines in the Amstrad firmware. See 'The Text VDU' section of http://www.cantrell.org.uk/david/tech/cpc/cpc-firmware/firmware.pdf for more details. TXT SET PEN will ...
Mark Williams's user avatar
2 votes

Change text color in Z80 assembly for Amstrad CPC 464

It's a simple solution, but the firmware information was not clear to me, just now I got it: org &4000 run &4000 ld a,2 ; Pen number 2 call &bb90 ; TXT SET PEN (light blue) ld A,65 ;...
reymagnus's user avatar
  • 173
2 votes

How exactly does the Apple II monitor set and use the "last opened" and "next changable" locations?

Okay stealing text from the Apple Monitor unpeeled: $31 MODE - This byte is used by the Monitor command processing routines to control parsing and to control operations when a blank is encountered ...
PeterI's user avatar
  • 5,297

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