Editing Acorn Archimedes (section)

===A5000 and A4 laptop===
[[File:Acorn Archimedes A5000 open.jpg|thumb|left|A5000 with top removed]]
In late 1991, the A5000 was launched to replace the A440/1 machine in the existing product range.<ref name="acornuser199111_a5000">{{ cite magazine | url=https://archive.org/details/AcornUser112-Nov91/page/n8/mode/1up | title=A5000 - PC Styling with RISC OS 3 and the Speed of ARM3 | magazine=Acorn User | date=November 1991 | access-date=18 April 2021 | pages=7 }}</ref> With the existing A400/1 series regarded as "a little tired", being largely unchanged from the A400 models introduced four years previously, the A5000 was regarded (by one reviewer, at least) as "the biggest leap forward for Acorn since the introduction of the Archimedes in 1987", introducing a combination of the ARM3 processor and RISC OS 3 for the first time in a new Acorn product, being "the machine the A540 should have been - smaller, neater, with higher capacity drives and all the same speed for about half the cost".<ref name="acornuser199112_a5000">{{ cite magazine | url=https://archive.org/details/AcornUser113-Dec91/page/n139/mode/2up | title=A5000 A Step in the Right Direction | magazine=Acorn User | date=December 1991 | access-date=18 April 2021 | last1=Bell | first1=Graham | pages=138–139, 141–142 }}</ref> The A5000 initially ran RISC OS 3.0, although several bugs were identified,<ref name="acornuser199211_riscos3" /> and most were shipped with RISC OS 3.10 or 3.11.

The A5000 featured the new 25&nbsp;MHz ARM3 processor, 2 or 4&nbsp;MB of RAM, either a 40&nbsp;MB or an 80&nbsp;MB [[hard drive]] and a more conventional [[Pizza box form factor|pizza box-style]] two-part case. With IBM-compatible PCs offering increasingly better graphical capabilities, they had not merely matched the capabilities of Acorn's machines, but in offering resolutions of {{nowrap|1024 × 768}} in 16 or 256 colours and with 24-bit palettes, they had surpassed them. The A5000 (along with the earlier A540) supported the [[SVGA]] resolution of {{nowrap|800 × 600}} in 16 colours, although the observation that "Archimedes machines have simply not kept pace" arguably remained.<ref name="acornuser199112_a5000" /> Earlier models could also benefit from the video performance of the A5000 via third party upgrades such as the Computer Concepts ColourCard Gold.<ref>{{cite web |url=http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/CC_ColourcardGold.html |title=Computer Concepts ColourCard Gold |publisher=Centre for Computing History |date=31 October 2008 |access-date=18 April 2021 }}</ref> The A5000 was the first Acorn machine to adopt the 15-pin [[VGA connector]].<ref name="archimedesworld199310_vga">{{ cite magazine | url=https://archive.org/details/acorn-archimedes-world-oct-1993/page/69/mode/1up | title=Acorn answers | magazine=Archimedes World | date=October 1993 | access-date=8 February 2022 | last1=Honey | first1=Chris | pages=69 }}</ref>

It was the first Archimedes to feature a [[Disk density#HD|high density]] capable [[floppy disc]] drive as standard. This natively supported various formats including [[DOS]] and [[Atari]] discs with formatted capacities of 720&nbsp;KB and 1.44&nbsp;MB. The native [[Advanced Disc Filing System|ADFS]] floppy format had a slightly larger capacity of 800&nbsp;KB for [[Disk density#DD|double density]] or 1.6&nbsp;MB for high density.<ref name="acornuser199111_a5000" /> A later version of the A5000 featured a 33&nbsp;MHz ARM3, 2 or 4&nbsp;MB of RAM, and an 80 or 160&nbsp;MB hard drive.<ref name="acornuser199311_revamp" /> Particularly useful in this revised A5000 was the use of a socket for the MEMC1a chip, meaning that memory expansions beyond 4&nbsp;MB could more easily replace the single MEMC1a, plugging in a card providing the two MEMC1a devices required to support 8&nbsp;MB.<ref name="acornuser199501_memory">{{ cite magazine | url=https://archive.org/details/AcornUser151-Jan95/page/n68/mode/1up | title=Double your memory | magazine=Acorn User | date=January 1995 | access-date=1 August 2021 | last1=Matthewman | first1=David | pages=69 }}</ref> Earlier revisions of the A5000 required desoldering of the fitted MEMC1a to provide such a socket.<ref name="acornuser199306_memory">{{ cite magazine | url=https://archive.org/details/AcornUser131-Jun93/page/n36/mode/1up | title=Improve your memory | magazine=Acorn User | date=June 1993 | access-date=1 August 2021 | last1=Lawrence | first1=David | pages=35 }}</ref>

[[File:Acorn A4-computer.png|thumb|A4 laptop]]
In 1992, Acorn introduced the A4 [[laptop]] computer featuring a slower 24&nbsp;MHz version of the ARM3 processor (compared to the 25&nbsp;MHz ARM3 in the A5000), supporting a 6&nbsp;MHz power-saving mode, and providing between 2.5 and 4 hours of usage on battery power. The machine featured a 9-inch passive matrix [[LCD]] screen capable of displaying a maximum resolution of {{nowrap|640 × 480 pixels}} in 15 levels of grey, also featuring a monitor port which offered the same display capabilities as an A5000. No colour version of the product was planned. A notable omission from the machine was a built-in [[pointing device]], requiring users to navigate with the cursor keys or attach a conventional Acorn three-button mouse, such as the [[Logitech]] mouse bundled with the machine.<ref name="acornuser199208_a4">{{ cite magazine | url=https://archive.org/details/AcornUser121-Aug92/page/n8/mode/1up | title=Unveiled at Last - Acorn's A4 | magazine=Acorn User | date=August 1992 | access-date=1 August 2021 | pages=7 }}</ref>

The other expansion ports available on the A4 were serial and parallel ports, a PS/2 connector for an external keyboard, a headphone connector, and support for an Econet expansion (as opposed to an Econet port itself). No other provision for expansion was made beyond the fitting of the Econet card and a hard drive. The A4 effectively fit an A5000 into a portable case, having a motherboard "roughly half the size of a sheet of A4 paper", adding extra hardware for power management and driving the LCD, the latter employing an Acorn-designed controller chip using "time-domain dithering" to produce the different grey levels. Just as the processor could be slowed down to save power, so the 12&nbsp;MHz RAM could be slowed to 3&nbsp;MHz, with various subsystems also being switched off as appropriate, and with power saving being activated after "more than a second or so" of user inactivity. The A4's case itself was used by Olivetti and [[Triumph-Adler]] models, particularly the Triumph-Adler Walkstation which did integrate a built-in pointing device, this being described as an "all-but-unusable touchpad mouse-controller" by one reviewer.<ref name="acornuser199208_a4_ok">{{ cite magazine | url=https://archive.org/details/AcornUser121-Aug92/page/n21/mode/2up | title=A4 OK? | magazine=Acorn User | date=August 1992 | access-date=1 August 2021 | pages=20–21, 23 }}</ref>

The launch pricing of the A4 set the entry-level model with 2&nbsp;MB of RAM at £1399 plus VAT, with the higher-level mode with 4&nbsp;MB of RAM and 60&nbsp;MB hard drive at £1699 plus VAT. Education pricing was £1099 and £1399 respectively. Acorn foresaw educational establishments taking to the machine where existing models were needing to be moved around between classrooms or taken on field trips,<ref name="acorn_a4">{{ cite press release | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/PR/A4_Launch.txt | title=Announcing Acorn's A4 Portable - "... a quart in a pint pot" | publisher=Acorn Computers Limited }}</ref> although review commentary noted that "the A4 is too expensive for schools to afford in large numbers" and that contemporary Apple and IBM PC-compatible models offered strong competition for business users.<ref name="acornuser199208_a4_ok" />

Peripherals for the A4 were eventually produced, with Acorn providing the previously announced Econet card, and with Atomwide providing Ethernet and SCSI adapters utilising the bidirectional parallel port present on the A4 (and also the A5000 and later machines). Atomwide also offered the "Hi-Point" trackball peripheral modified to work as an Acorn-compatible mouse which attached to the side of the unit.<ref name="acornuser199309_a4">{{ cite magazine | url=https://archive.org/details/AcornUser134-Sep93/page/n50/mode/1up | title=On the Move | magazine=Acorn User | date=September 1993 | access-date=2 August 2021 | last1=Lawrence | first1=Dave | last2=Burley | first2=Ian | pages=49–50 }}</ref>