ROM is Read Only Memory and is used widely in the electronics industry as a standard storage for program and data on hardware.
Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware (software that is closely tied to specific hardware, and unlikely to need frequent updates) or application software in plug-in cartridges.
https://en.wikipedia.org/wiki/Read-only_memory for more info on how it works.
- ROM cartridges can not be used on a Version 2.2 QI model 99/4a due to changes made in the operating system to block non-TI cartridges. See here for more info on working around this.
- Some ROM cartridges were made that plugged in to the side port to bypass QI protection as well. Arcturus and Miner 2049er for examples. They work on all versions of the console.
- ROM cartridge boards are available from 8k to 2mb
New production cartridge boards for the TI-99/4a
GROM is a TI propitiatory standard memory device only found on TI-99 and compatible systems.
- This is a technical write up on the GROM: http://www.unige.ch/medecine/nouspikel/ti99/groms.htm
- All carts released from Texas Instruments contain at least one GROM chip
- GROM chips are the storage medium for the GPL programming language developed by TI
- GROM chips were never available to manufacture outside of TI’s control
Some interesting devices were made to get around TI’s GROM restrictions including:
- Gram Kracker from Miller’s Graphics – http://mainbyte.com/ti99/hardware/gram/gramk.html
- Pgram: http://www.unige.ch/medecine/nouspikel/ti99/pgram.htm
- Pgram+: http://mainbyte.com/ti99/hardware/peb/pgram.htm
- 128k Gram Karte: http://www.unige.ch/medecine/nouspikel/ti99/gramkart.htm
- UberGROM: The UberGROM alows us to build any cartridge that was made for the TI in the past due to it’s ability to store 512k of ROM and 128k of GROM in a single board. Designed and built by Tursi, Ksarul and Acadel. Available here:
- FinalGROM99 was just released by Ralph Benzinger and supports loading ROM and GROM images from a SD card more info here: http://atariage.com/forums/topic/260917-the-finalgrom-99/page-10?do=findComment&comment=3802011 and a pre-built cartridge library for the sdcard is here: http://ftp.whtech.com/Cartridges/FinalGROM99/