Editing Commodore 128 (section)

== C128D ==
[[file:Commodore 128D-IMG 1726.jpg|thumb|Commodore 128D on display at the [[Musée Bolo]], [[École Polytechnique Fédérale de Lausanne|EPFL]], Switzerland]]
[[file:Psfan01.jpg|thumb|Commodore 128DCR [[switch-mode power supply]], fitted with a 60&nbsp;mm cooling fan]]

Late in 1985, Commodore released a new version of the C128 with a redesigned chassis resembling the [[Amiga 1000]]. Called the Commodore 128D, this new European model featured a plastic chassis with a carrying handle on the side, incorporated a 1571 disk drive into the main chassis, replaced the built-in keyboard with a detachable one, and added a [[Computer cooling#Desktops|cooling fan]]. The keyboard also featured two folding legs for changing the typing angle.<ref name="Computing History 2024 x197">{{cite web | title=Commodore 128D | website=Computing History | date=January 9, 2024 | url=https://www.computinghistory.org.uk/det/7652/Commodore-128D/ | access-date=January 9, 2024}}</ref>

The C128 released in the United Kingdom on 25 July 1985,<ref>{{cite magazine |title=Special Feature: Happy Birthday! |magazine=[[Popular Computing Weekly]] |date=1 May 1987 |pages=14–18 (18) |url=https://archive.org/details/popular-computing-weekly-1987-05-01/page/n17}}</ref> and in North America in November 1985.<ref name="CE1985">{{cite magazine |title=1985 Index |magazine=[[Computer Entertainer]] |date=January 1986 |volume=4 |issue=10 |page=6 |url=http://www.ataricompendium.com/archives/newsletters/video_game_update/computer_entertainer_jan86.pdf#page=6}}</ref>

According to Bil Herd, head of the Hardware Team (a.k.a. the "C128 Animals"), the C128D was ready for production at the same time as the regular version. Working to release two models at the same time had increased the risk for on-time delivery and was apparent in that the main PCB has large holes in critical sections to support the C128D case and the normal case concurrently.{{citation needed|date=December 2023}}

In the latter part of 1986, Commodore released a version of the C128D in North America and parts of Europe referred to as the C128DCR, CR meaning "cost-reduced". The DCR model features a stamped-steel chassis in place of the plastic version of the C128D (with no carrying handle), a modular [[switched-mode power supply]] similar to that of the C128D, retaining that model's detachable keyboard and internal 1571 floppy drive. A number of components on the [[mainboard]] were consolidated to reduce production costs and, as an additional cost-reduction measure, the [[computer cooling|cooling fan]] that was fitted to the D model's power supply was removed. However, the mounting provisions on the power supply subchassis were retained, as well as the two 12-volt DC connection points on the power supply's [[printed circuit board]] for powering the fan. The C128DCR mounting provision is for a 60&nbsp;mm fan.{{citation needed|date=December 2023}}

A significant improvement introduced with the DCR model was the replacement of the 8563 video display controller (VDC) with the more technically advanced [[MOS Technology 8568|8568 VDC]] and equipping it with 64 KB of video RAM—the maximum amount addressable by the device. The four-fold increase in video RAM over that installed in the "flat" C128 made it possible, among other things, to maintain multiple text screens in support of a true windowing system, or generate higher-resolution graphics with a more flexible color palette. Little commercial software took advantage of these possibilities.{{citation needed|date=December 2023}}

The C128DCR is equipped with new ROMs dubbed the "1986 ROMs", so-named from the copyright date displayed on the power-on banner screen. The new ROMs address a number of [[computer bug|bugs]] that are present in the original ROMs, including an infamous [[off-by-one error]] in the keyboard decoding table, in which the {{keypress|Q}} character would remain lowercase when {{keypress|CAPS LOCK}} was active. Some software will only run on the DCR, due to dependencies on the computer's enhanced hardware features and revised ROMs.{{r|randall198906}}

Despite the DCR's improved RGB video capabilities, Commodore did not enhance BASIC 7.0 with the ability to manipulate RGB graphics. Driving the VDC in graphics mode continues to require the use of calls to screen-editor ROM [[machine code|primitives]] or their [[assembly language]] equivalents,<ref>{{cite magazine|url=https://archive.org/stream/run-magazine-26/Run_Issue_26_1986_Feb#page/n35/mode/2up |title=Ultra Hi-Res Graphics — A Breakthrough On Your C-128|pages=34–39|first1=Louis R|last1=Wallace|first2=David P|last2=Darus |magazine=[[Run (magazine)|RUN]] |volume=3 |issue=2 #26|date=February 1986}}</ref> or by using third-party BASIC language extensions, such as Free Spirit Software's "[[BASIC 8]]", which adds high-resolution VDC graphics commands to [[BASIC 7.0]].{{citation needed|date=December 2023}}