Editing Amiga 1000 (section)

== Technical information ==
The preproduction Amiga (which was codenamed "Velvet") released to developers in early 1985 contained {{nowrap|128 KB}} of RAM with an option to expand it to {{nowrap|256 KB.}} Commodore later increased the system memory to {{nowrap|256 KB}} due to objections by the Amiga development team. The names of the custom chips were different; Denise and Paula were called Daphne and Portia respectively. The casing of the preproduction Amiga was almost identical to the production version: the main difference being an embossed Commodore logo in the top left corner. It did not have the developer signatures.<ref>{{Cite web|title = Amiga 1000 Developer "Velvet" - computer collection vienna ENG|url = http://scacom.bplaced.net/Collection/velvet/velveten.php|website = scacom.bplaced.net|access-date = 2015-08-23|first = Stefan|last = Egger}}</ref>

The Amiga 1000 has a [[Motorola 68000]] CPU running at 7.15909&nbsp;[[Hertz|MHz]] on [[NTSC]] systems<ref name=Byte/>{{Rp|87}} or 7.09379&nbsp;MHz on [[PAL]] systems, precisely double the video color [[carrier frequency]] for NTSC or 1.6 times the color carrier frequency for PAL. The system clock timings are derived from the video frequency, which simplifies [[glue logic]] and allows the Amiga&nbsp;1000 to make do with a single [[crystal oscillator|crystal]]. In keeping with its video game heritage, the chipset was designed to synchronize CPU memory access and chipset [[direct memory access|DMA]] so the hardware runs in real time without wait-state delays.

Though most units were sold with an analog [[RGB color model|RGB]] monitor, the A1000 also has a built-in [[composite video]] output which allows the computer to be connected directly to some monitors other than their standard RGB monitor. The A1000 also has a "TV MOD" output, into which an RF Modulator can be plugged, allowing connection to older televisions that did not have a composite video input.

The original 68000 CPU can be directly replaced with a [[Motorola 68010]], which can execute instructions slightly faster than the 68000 but also introduces a small degree of software incompatibility. Third-party CPU upgrades, which mostly fit in the CPU socket, use faster [[Motorola 68020|68020]] or [[Motorola 68030|68030]] microprocessors and integrated memory, as well as provide support for a [[Motorola 68881|68881]] or [[Motorola 68881#68882|68882]] [[Floating-point unit|FPU]]. Such upgrades often have the option to revert to 68000 mode for full compatibility. Some boards have a socket to seat the original 68000, whereas the 68030 cards typically come with an on-board 68000.

The original Amiga&nbsp;1000 is the only model to have 256&nbsp;[[kilobyte|KB]] of [[Amiga Chip RAM]], which can be expanded to 512&nbsp;KB with the addition of a [[daughterboard]] under a cover in the center front of the machine.<ref name="a1000_intro">{{Cite book| url=http://www.bombjack.org/commodore/amiga/amiga-commodore/Amiga_1000_Introduction.pdf | title=Introduction to the Amiga | publisher=Commodore-Amiga, Inc. | year=1986 | access-date=August 26, 2011 | archive-url=https://web.archive.org/web/20120613032259/http://www.bombjack.org/commodore/amiga/amiga-commodore/Amiga_1000_Introduction.pdf | archive-date=June 13, 2012 | url-status=dead | df=mdy-all }}</ref> RAM may also be upgraded via official and third-party upgrades, with a practical upper limit of about 9&nbsp;[[Megabyte|MB]] of "fast RAM" due to the 68000's 24-bit [[address bus]]. This memory is accessible only by the CPU permitting faster code execution as DMA cycles are not shared with the chipset.

The Amiga 1000 features an 86-pin expansion port (electrically identical to the later [[Amiga 500]] expansion port, though the A500's connector is inverted). This port is used by third-party expansions such as memory upgrades and [[SCSI]] adapters. These resources are handled by the Amiga [[Autoconfig]] standard. Other expansion options are available including a bus expander which provides two [[Amiga Zorro II|Zorro-II]] slots.

=== Specifications ===
[[File:JayMiner Mitch.jpg|thumb|[[Jay Miner]]'s signature from the top cover of a Commodore Amiga&nbsp;1000 computer. The paw print is that of Mitchy, Miner's dog.]]
[[File:Amiga 1000 Back.jpg|thumb|Rear view of the A1000]]
{| class="wikitable"
|-
! Attribute
! Specification<ref name="a1000_intro"/>
|-
| [[Central processing unit|Processor]]
| [[Motorola 68000]] at 7.16&nbsp;MHz ([[NTSC]]) or 7.09&nbsp;MHz ([[PAL]])
|-
| RAM
| 256&nbsp;[[kilobyte|KB]] of [[Amiga Chip RAM]]; upgradeable to 512&nbsp;KB by dedicated cartridge; max. 8 MB Fast RAM with external cartridge
|-
| ROM
| 8&nbsp;KB [[Bootstrapping|bootstrap]] ROM. 256&nbsp;KB WCS reserved for OS (loaded from the [[Kickstart (Amiga)|Kickstart]] [[Floppy disk#3.C2.BD-inch floppy disk|floppy disk]] at power-on)
|-
| Chipset
| [[Original Chip Set]] (OCS)
|-
| Video
| 12-bit color palette (4096&nbsp;colors). Graphic modes with up to 32, 64&nbsp;([[Amiga Halfbrite mode|EHB]] mode; Early NTSC models do not have the EHB mode) or 4096 ([[Hold-And-Modify|HAM]] mode) on-screen colors:

* 320×200 to 320×400[[Interlaced video|i]] (NTSC)
* 320×256 to 320×512i (PAL)

Graphic modes with up to 16 on-screen colors:

* 640×200 to 640×400i (NTSC)
* 640×256 to 640×512i (PAL)
|-
| Audio
| 4× 8-bit [[Pulse-code modulation|PCM]] channels (2 [[Stereophonic sound|stereo]] channels); 28&nbsp;kHz maximum [[Direct memory access|DMA]] [[Sampling (signal processing)#Sampling rate|sampling rate]]; 70&nbsp;dB [[Signal-to-noise ratio|S/N ratio]]
|-
| Removable storage
| 3.5-inch [[Double density|DD]] [[floppy disk]] drive (880&nbsp;KB capacity)
|-
| Audio/video out
| Analog RGB video out ([[D-subminiature|DB-23M]]); TV MOD audio/video output (for Amiga RF modulator TV connection); Composite video out ([[RCA connector|RCA]]); Audio out (2× RCA)
|-
| Input/output ports
| Keyboard port ([[RJ10]]); 2× mouse/gamepad ports ([[D-subminiature|DE9]]); [[RS-232]] [[serial port]] (DB-25F); Centronics style [[parallel port]] (DB-25M); [[floppy disk]] drive port (DB-23F)
|-
| Expansion slots
| 86-pin expansion port
|-
| [[Operating system]]
| [[AmigaOS]] 1 (Kickstart 1.0/1.1/1.2/1.3 and [[Workbench (AmigaOS)|Workbench]] 1.0/1.1/1.2/1.3)
|}