Questions tagged [rom]

For questions about Read Only Memory.

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117
votes
2answers
21k views

How did Commodore's anti-Microsoft Easter Egg work?

A couple years ago the Toronto PET Users Group published an article (The Great Commodore/Microsoft Easter Egg War, on p. 7) about a newly discovered anti-Microsoft Easter Egg that Commodore hid in the ...
46
votes
4answers
7k views

Why would older video games include fragments of source code?

One thing that was surprisingly common in older video games (around the same era assembly language was king) was the inclusion of uncompiled, plaintext source code in the ROM. You can see many ...
39
votes
8answers
11k views

Why is EEPROM called ROM if it can be written to?

Is there a historical reason? Since it is rewritable it isn't read only by definition, so why call it so?
32
votes
7answers
5k views

Is it legal to download ROM images from shared or internet archives?

Is it generally legal to download older ROM images of commercial software and games for non-commercial use in a retro computing system (emulated or otherwise)? (Note that this question implies no ...
22
votes
6answers
5k views

How do arcade ROMs work

The way I understand it, ROMS are like virtual games, and emulators are like virtual game consoles, or handhelds. What I don't understand is how there are ROMs for arcade games, which don't have ...
17
votes
3answers
978 views

What is the relationship between solid-state ROM and inaccessible content in arcade games?

I was browsing through tcrf.net, which specializes in displaying unused programming and content left in games by developers, and came across this page: https://tcrf.net/Tank Specifically, the ...
16
votes
4answers
2k views

Historical price of ROM

Historical price charts for RAM are quite readily available, e.g. in the mid-seventies a ballpark figure was a penny a byte. What was the price of ROM (assuming you were getting the chips produced in ...
16
votes
4answers
2k views

Best way to locate data on ROM? (6502 Processor)

Lately I've been interested in how old machines work, in particular an NES. While there are quite a few resources on the basic operations and even some games that have been totally broken down byte by ...
15
votes
1answer
944 views

Why did POKEing ROM addresses mask port writes?

After reading mcleod_ideafix's answer about the Inves Spectrum+'s "randomize of death", specifically his article on the subject, one thing struck me as odd. From César Hernández Bañó's research: ......
15
votes
3answers
2k views

Speed of early ROM versus RAM chips

In the late seventies, up through around 1981, the maximum access speed of off-the-shelf RAM chips was around 2.6 MHz. Did the same speed limit apply to ROM chips of the same era? If not, what would ...
14
votes
3answers
2k views

What is the Circuit for a 16K or 32K MSX computer cartridge?

This question is about the old MSX-1 computers. I have a game I wrote, as a ROM file, and I now want to play it on a real MSX computer by putting the game into cartridge form. The game has been ...
14
votes
2answers
739 views

Can I trigger the Amiga ROM debugger from the boot prompt?

Suppose I have an Amiga computer without any working boot disks. Is it possible to trigger the built-in ROM monitor (RomWack or SAD, see https://theamigamuseum.com/amiga-kickstart-workbench-os/guru-...
13
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3answers
3k views

Extended ROMs on the Amiga CD32 and CDTV

Continuing my series of questions about Amiga ROMs :-) The Commodore CDTV contained a normal Kickstart 1.3 ROM, plus an "extended ROM". From http://www.l8r.net/technical/cdtv-technical.html: The ...
12
votes
3answers
2k views

Decoding Logic and Memory Systems for 8-bit computer - 64K address space

I am creating a minimal Z80 computer with serial output on a breadboard. I have kind of moved up from the last question, where I was executing instructions on Z80 using specific connection of ...
12
votes
1answer
1k views

Did the Apple 1 cassette interface card have its own ROM?

According to this page, the Apple 1 monitor program was located in addresses $F000-$FFFF, a ROM program to use the optional cassette interface card was at addresses $C100-$C1FF, and the peripheral ...
12
votes
1answer
447 views

What's the difference between Williams Earthshaker pinball ROMs L-3 and F-1?

I acquired a Williams "Earthshaker!" pinball machine several years ago. It came with the version L-1 ROM installed. I noticed that sometimes balls would get stuck in the shelter kick-back-up mechanism ...
11
votes
2answers
6k views

What did the Supercard “patch” program actually do to GBA and NDS ROMs to make them playable?

The Supercard is a flash cart for the Game Boy advance which can play ROMs and other files off of assorted flash memory. I recently found my Supercard SD and Superkey for NDS, which acts as a ...
11
votes
1answer
793 views

Does an Apple //e actually have 64KB of RAM?

Inspired by this question about the C64, I was curious if the Apple //e (and I suppose //c and IIgs, though not sure of ][+) somehow had a similar behavior. In short, we know that the Apple ROMs start ...
11
votes
1answer
634 views

Can the system's BIOS come from an ISA card?

If an ISA card was configured to respond to the address range of the system's BIOS (and the BIOS chips removed), could you boot from it in the same way as the system's default BIOS? Specifically, I'm ...
11
votes
0answers
877 views

Did Hewlett Packard really allow the use of the HP48 ROMs in emulators?

On the FAQ of the emu48 software, a famous emulator for HP38/39/40/48/49 calculators (http://hp.giesselink.com/emu48faq.htm#ROM), we can find the following assertion: In general all HP-ROM files ...
10
votes
1answer
1k views

How can a Game Boy game “glitch-inherit” the music from a different game like this?

Just now, I saw a stream of a person playing Game Boy games. The technical setup is like this: Real American SNES. Real Super Game Boy 2. (Only released in Japan; fixes the speed bug in the Super ...
10
votes
1answer
1k views

What kind of EPROM was used for the Apple //e character generator, and how do I write a new one?

I have an old Apple //e clone, bought in Brazil (but assembled who-knows-where-on-Earth) that has not been touched for over 15 years. At least, from what I could see, it is a //e -- but not enhanced, ...
9
votes
3answers
2k views

Algorithm for Apple IIe and Apple IIgs boot/start beep

What is algorithms use for boot/start sound (when turn on computer) in Apple IIe and Apple IIgs? I can't find information about Apple boot sound algorithms or where in computer ROM store either ...
9
votes
5answers
2k views

C64 cartridge emulation with ATmega

As a personal project I had the idea to create a custom cartridge for my Commodore 64 and use an ATmega 1284p microcontroller to emulate eproms and/or custom chips. Basically my idea is similar to ...
9
votes
2answers
524 views

Homemade ROM cartridge for Thomson TO7/70 home computer

I recently acquired a Thomson TO7/70 home computer. It came without any MEMO7 cartridges (ROM cartridges) that are necessary to properly use it. I found images of the ROMS, and a schematic, so in ...
9
votes
2answers
3k views

How to get a dump of a particular ROM?

How do I create a dump of a Game Boy game so that I can have it for backup as a ROM? I know that I can download the ROM (though slightly illegal) if I really wanted to, but I want to know "how" ROM ...
9
votes
1answer
209 views

Can you switch the ZX81 ROM to RAM w/o write protecting it and still use ZX81 BASIC?

I built an external 8K RAM circuit that replaced the 8K ROM of Sinclair ZX81 and I also pulled out address lines from the ULA (dogsbody) so that character generation worked. I wrote a small machine ...
9
votes
1answer
569 views

Can you program an arcade game and have MAME or another emu run it?

I know Mame works with drivers for each game or hardware, and it checks for specific ROMs, and I guess it might check also for some checksum to verify the ROMs integrity. Is there some way you could ...
9
votes
1answer
748 views

Restore original ROM on PalmOne m515

I've recently bought an old Palm m515 PDA. It seems that the previous owner has removed some of the built-in applications like Calendar and Contacts from it, because when I want to start them it says ...
9
votes
1answer
334 views

Patch BBC Master ROM using Sideways RAM?

I have a BBC Master 128 with the standard ROM installed. This includes ADFS v1.50 in slot "D". I want to replace this ADFS in ROM with a patched version, loaded from disk, into Sideways RAM. It is a ...
8
votes
4answers
764 views

Does fast page mode apply to ROM?

Starting with the 4116, RAM chips from the late seventies supported fast page mode, where if you were reading nearby – particularly, successive – words, you didn't need to supply both row and column ...
8
votes
2answers
851 views

What does it mean to byte swap or split a ROM image?

I'd like to understand: What does it mean to "byte swap" when burning kickstart or extended ROMs? Is it the same as "splitting" the ROM? How is it done and why?
8
votes
2answers
98 views

Is there any persistent storage in a NEC MobilePro PocketPC?

I have recently acquired a NEC MobilePro 790 PocketPc from 2001. The specifications says that the device has 48MB memory, including 32MB of RAM and 16MB of flash storage. It also has a ROM that ...
7
votes
5answers
1k views

Maximum size of 8-bit computer cartridges

What was the largest cartridge produced, or possible, for any 8-bit home computer? That is, the later 8 or 16-bit console cartridges could be surprisingly large, up to several megabytes in some cases,...
7
votes
1answer
612 views

Did any SNES games use the fast ROM?

According to the transcript at https://fabiensanglard.net/another_world_polygons_SNES/ ... I could get the software running again to run at about 30 frames per second if of course I'm using a fast ...
7
votes
2answers
492 views

Is it safe for C64 cartridges to respond to read and/or write requests on “unmapped” addresses?

According to the C64 wiki, asserting G̅A̅M̅E̅ on the cartridge port (and not asserting E̅X̅R̅O̅M̅) of the C64 leaves three blocks of the C64 address space "unmapped": 28 KB @ $1000 (otherwise RAM), 8 ...
7
votes
1answer
406 views

ROM programs on the Sony MSX HitBit HB-501

I have acquired a Sony MSX HB-501 F (F stands for France, it only defines the keyboard's layout). It is fully functionnal, I can play games from cartridges on it and it displays MSX-BASIC if no ...
6
votes
2answers
911 views

Arcade games in Apple IIc's ROM

Is there a website where I can find the old games that where pre-installed in the Apple IIc ROM? When I could not get an OS disk, I could still have some fun with my Apple IIc by playing those arcade ...
6
votes
2answers
2k views

What does “ByteSwapped” and “BigEndian” refer to in the context of video game ROMs?

I have found two different sets of Nintendo 64 ROMs with the same games (which, of course, I physically own). One is labeled "ByteSwapped" and the other "BigEndian". What exactly ...
6
votes
2answers
2k views

Dumping Nintendo 64 cartridges without a backup device

I've seen various posts online about Nintendo cartridge dumping. Two popular posts which come to mind are Thijs Alkemade's Game Boy cartridge dumping on a Raspberry Pi series and NintendoPlayer's ...
6
votes
1answer
533 views

Can the Nintendo 64 run code directly from ROM?

I've read that the usual way to execute code on the N64 is to use DMA to copy it from ROM into RAM, and then run from RAM. However, it seems that the contents of the ROM are directly visible to the ...
5
votes
4answers
370 views

Cheapest type of Read-Only Memory allowing Random access before Year 1970

Back in the 50s and 60s people had: random access, read-write memories like Magnetic Cores. sequential access, read-write memories like Delay Lines and Magnetic Tapes. And: sequential access, write ...
5
votes
1answer
489 views

Hitachi HD630x executable format

Can anyone tell me what executable format the Hitachi HD630x series of MPUs used? I'm looking to disassemble (out of curiosity) a binary for the Hitachi HD63A03XP microprocessor. In case anyone is ...
5
votes
1answer
945 views

What was the purpose of GROM (vs ROM) in the TI-99/4a?

The TI-99/4a had a cartridge slot on the front of the computer which accepted "solid state cartridges" (as TI called them). These cartridges would typically contain ROM (Read Only Memory) like many ...
5
votes
1answer
321 views

Collection of older EPROM IC's

I acquired a collection of older EPROM IC's and am wondering what the rarity of them are or if they are rather common. Do people collect these items? 89142 NM27C512Q ~~ B9212 NM27C512Q ~~ B9312 ...
5
votes
2answers
339 views

How to debug BIOS ROM incompatibility?

I'd like to use the XT-IDE Universal BIOS with an IBM XT 286 (5162), but it's known to be incompatible. With the card installed, it will not boot from a floppy from which it would otherwise boot (it ...
5
votes
2answers
314 views

Dimensioned drawing of 64-pin SIMM?

I am looking for a dimensioned drawing of a 64-pin SIMM PCB like the ones used in the Macintosh II series for the ROM SIMM. I looked in Guide to the Macintosh Family Hardware and Designing Cards and ...
4
votes
4answers
681 views

What home computer was the first to use a external ROM cartridge?

When was the external ROM cartridge first used and what home computer was the first to use it?
4
votes
1answer
309 views

List of Intel microchips

Where could I find a list of all of the microchips released by Intel, including microprocessors, Rams, roms, storage devices. Etc. I have checked Wikipedia, and they have the processors, but not any ...
4
votes
2answers
209 views

C64 KERNAL Loading into I/O space [duplicate]

On a Commodore 64, if I Load "*",8,1 and the file's address (first two bytes on disk) is $D000, will it load to the RAM under the I/O space? In other words, does the KERNAL loader properly ...