Chip RAM is the name given to RAM in the Amiga computer that could be accessed by the custom chipset as well as the CPU. The custom chipset was able to perform DMA transfers to and from this RAM, and would even lock-out the CPU while doing so. To meet Wikipedias quality standards, this article or section may require cleanup. ... The original Amiga (1985) The Amiga is a family of home/personal computers originally developed by Amiga Corporation as an advanced game console. ... OCS is a three-letter-acronym (or TLA) that may stand for: Carbonyl sulfide Obsessive-compulsive scale Obsessive-compulsive symptoms Ocean Colour Scene Office of Career Services (several) Office of the Chief Scientist (Australia) Office of Coast Survey (NOAA) Office coffee service Office of Community Services Office of Cyberspace Security... Intel 80486DX2 microprocessor in a ceramic PGA package A central processing unit (CPU), or sometimes simply processor, is the component in a digital computer that interprets instructions and processes data contained in software. ... Direct memory access (DMA) allows certain hardware subsystems within a computer to access system memory for reading and/or writing independently of the CPU. Many hardware systems use DMA including disk drive controllers, graphics cards, network cards, and sound cards. ...

By default, most Amiga computers only came with chip RAM, but could be expanded with RAM (called "Fast RAM") that only the CPU could access, even when the custom chipset was simultaneously accessing chip RAM.

The amount of chip RAM varied between different Amiga models, although generally newer models had more chip RAM than older ones. The original Amiga 1000 was the only model to only have 256 kilobytes of chip RAM. Its more popular successors, the Amiga 500 and Amiga 2000, had 512 kilobytes. The Amiga 500 Plus, Amiga 600, later versions of the A2000, and the Amiga 3000 had a full megabyte of chip RAM, and the last models, the Amiga 1200 and Amiga 4000, had two megabytes. The A500+, A600 and A3000 were upgradable to 2Mb of Chip RAM. The Amiga 4000 motherboard includes a jumper that claims to accommodate eight megabytes of chip RAM, but this jumper is broken - regardless of its position, the computer will only recognise two megabytes. Amiga 1000 (1985) The A1000, or Commodore Amiga 1000, was Commodores initial Amiga multimedia home/personal computer, released in the summer of 1985 at an original retail price of US$1,295 without a monitor. ... A kilobyte (derived from the SI prefix kilo-, meaning 1000) is a unit of information or computer storage equal to either 1024 or 1000 bytes. ... Missing image A500 The A500, also known as the Amiga 500, was the first low-end Commodore Amiga 16_bit multimedia home/personal computer model. ... The A2000, also known as the Commodore Amiga 2000, is the high-end Amiga personal computer that was released in 1987 at the same time as the low-end high-volume model A500. ... The Commodore Amiga 500 Plus, (A500+) is an enhanced version of the original Amiga 500. ... The A600, also known as the Amiga 600 (codenamed June Bug after a B-52s song), was an Amiga personal computer launched in March 1992. ... The A3000, also known as the Commodore Amiga 3000, was a much more serious proposition to build a professional multimedia computer than the previous A2000 effort. ... A megabyte is a unit of information or computer storage equal to approximately one million bytes. ... The Amiga 1200, or A1200, was Commodore Internationals third-generation Amiga computer, aimed at the home market. ... Amiga 4000T The A4000, or Commodore Amiga 4000, was the successor of the A2000 and A3000 computers. ... An old Octek Jaguar V main board with an AMD 386DX-40 processor. ...

The amount of addressable Chip RAM is dependent on the Agnus chip revision.

The original Amiga 500 had a trapdoor on the underside of the machine that took an upgrade to 1 megabyte of RAM. The extra 512 kilobytes was Fast RAM, but was sometimes refered to as Slow RAM since due to the design of the Trap door slot this RAM was slower than true Fast RAM. The trap door expansion usually included a clock that was battery-backed up. Later revisions of the A500 could have the trap door RAM configured as Chip RAM by a simple hardware modification.

Most revisions of the A2000 and A500 could be upgraded to 2Mb Chip RAM using a third party upgrade. The A1000 replacement motherboard "Phoenix" featured 2Mb of Chip RAM.

The UAE Amiga emulator allows the emulation of up to 8Mb of Chip RAM. UAE (or UNIX Amiga Emulator) is a free software designed to run software written for the Amiga range of computers. ...