Questions tagged [rom]

For questions about Read Only Memory.

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0answers
179 views

Problem with hackrom on real GBA cartridge

This is a problem that has brought me headaches, so I will try to explain as best as possible. I have flashed with a Gbxcart several GBA ROMs in real cartridges (repro), working without any problem, ...
8
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2answers
845 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?
9
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1answer
208 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
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2answers
523 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 ...
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2answers
157 views

How many kinds of mass-producible ROM is avaliable before 1970? [duplicate]

Back in the days before mask ROM (when invented?) we got core rope memories, or Little Old Ladies memories, which required lots of human labor to build. Were there any kinds of ROMs which were ...
39
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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?
4
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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 ...
1
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1answer
122 views

How to flash CDTV extended ROM using development board

I have a CDTV ROM development board, and I know it is possible to flash it using floppies. How to make such floppy with a custom rom?
7
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1answer
611 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 ...
12
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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 ...
3
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1answer
375 views

How did Woz get the Apple 1 monitor program into ROM?

Unlike the Apple ][, the Apple 1 never had BASIC in ROM. The Apple 1 booted into a monitor program, which enabled the user to type in machine code for a program (as Steve Wozniak often did), or load ...
5
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4answers
369 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
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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 ...
3
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2answers
1k views

How can I get MAME to run modified ROMs whose checksums don't match the originals?

In the aftermath of the question about running the arcade Pac-Man ROM on a Sinclair ZX Spectrum I discovered that about the same time that was done, somebody else did the reverse, porting a classic ...
0
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2answers
219 views

CPU slaves on a PCI card to retrofit single processor to multiple processors. Any ideas how? [closed]

My desktop computer is no longer manufactured and no longer supported since more than 18 years ago. It was a very expensive top of the line business computer back in the day. I like it and wish to ...
16
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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 ...
4
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1answer
186 views

Macintosh II ROM Replacement

I'd like to upgrade my Macintosh II to FDHD, I have a SWIM chip (to replace the WIM chip), but don't know how to burn the ROMS. The upgrade process I'm trying to do is described in the book: "...
10
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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 ...
9
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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 ...
0
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0answers
79 views

How to burn CDTV extended ROM image to eeproms

I have a patched version of CDTV extended rom, which I need to burn to 2 chips. I have 2 ST M27C1000 with pin swap adapter (pins 2 & 24 - M27C1001), TL866 mini pro programmer, hex editor and I was ...
2
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0answers
105 views

advice for retrieving functions and tables from intel 8061/8065 bin file (reverse engineering) from Ford EECV ECU

I have under my disposal some Ford EECV bin files and my goal for the next few weeks is to retrieve the functions and tables and plot them out before going onto DIY hardware . . Does anyone know which ...
2
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1answer
255 views

How likely is it that a ROM could be “corrupted” resulting in visual artifacts during gameplay? [closed]

I watch a lot of retro game streams. Frequently, whether they are running on a software emulator, hardware emulator (Retron 5 or whatever), or an Everdrive, whenever there is some weird glitch in the ...
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1answer
408 views

Why are there no actual complete and 100% verified/vetted ROM collections still? [closed]

Recently, I've been searching far and wide to collect, in digital form, the exact games that I owned as a child, or had temporarily, or rented/borrowed/played at somebody else's house, or never really ...
4
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2answers
759 views

Every single ROM in my collection has the wrong SHA1 hash according to No-Intros

I have a collection of ROM files for the NES, SNES, Nintendo 64 and others. These ROMs match exactly those games that I own or owned growing up. Recently, I found out about the "No-Intros" ...
-6
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1answer
723 views

Why is Sega Saturn mysteriously missing from No-Intros.org's hash database? [closed]

https://datomatic.no-intro.org/index.php?page=download This website has the worst, most cryptic and broken interface I've ever seen in my life, but eventually, I managed to download a big archive ...
6
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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 ...
117
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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 ...
3
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1answer
276 views

How do you switch ROM banks on Gameboy MBC2 Cart with INLRetro dumper

I have an INLRetro cart dumper. The software for the device is incomplete and in beta form. I've been able to dump Tetris and it works (because it's ROM fits into bank 0). When I attempt to dump ...
9
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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 ...
4
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2answers
292 views

What is the purpose of ROM switcher mods in CDTV

I've seen a lot of information on CDTV ROM switchers, but it is still unclear to me what is the actual purpose of it. As I understand it allows some compatibility with A500 games, but this disables CD ...
12
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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 ...
4
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1answer
134 views

How was the second bank of Apple IIc ROM accessed?

The original Apple IIc had a 27128 16 KB ROM mapped into the $C100-$FFFF range (the $C000 page was decoded for I/O). According to the Apple IIc Technical Reference Manual the ROMEN1* and ROMEN2* ...
15
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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: ......
3
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1answer
229 views

“Genesis Lock-On Technology” to change the language of a Famicom game

I want to create a cartridge similar to Sonic & Knuckles or a Game Genie so that the text files loaded from the ROM or DEPROM of an original Famicom cartridge can be replaced with alternate ...
4
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2answers
618 views

ZX Spectrum: What is the “T” state value, with reference to sound?

I have that awesome book - Zx Spectrum ROM Disassembled (correct the title if I got it wrong), where the author wrote about the audio code in the ROM and referring to "T" state, "... T200... T5000, ...
9
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1answer
568 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 ...
14
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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 ...
16
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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 ...
6
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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 ...
7
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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 ...
15
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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
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2answers
738 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-...
7
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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,...
1
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1answer
228 views

Expanded Ram Options for the TRS-80 Model 100 possible into the megabyte range?

I have a trs-80 model 100. I have all the option rams used. I've seen some quite useful ideas from other collectors on the internet for other TRS-80 model computers of using mouser electronic parts to ...
5
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2answers
313 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 ...
9
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1answer
333 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 ...
3
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2answers
2k views

Commodore Amiga 600 Software Failure. “Error: 8000 0004 Task: 000026D0”

Software Failure on Commodore Amiga 600 when I insert a floppy in drive. Software Failure. Press left mouse button to continue. Error: 8000 0004 Task: 000026D0 Independent from the floppy I ...
8
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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 ...
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 ...
22
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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 ...