Editing Macintosh Plus (section)

== Overview ==
[[Bruce Webster]] of ''[[Byte (magazine)|BYTE]]'' reported a rumor in December 1985: "Supposedly, Apple will be releasing a Big Mac by the time this column sees print: said Mac will reportedly come with 1 [[megabyte]] of RAM ... the new 128K-byte ROM ... and a double-sided (800K bytes) disk drive, all in the standard Mac box."<ref name="webster198512">{{cite magazine | url=https://archive.org/stream/byte-magazine-1985-12/1985_12_BYTE_10-13_Computer_Conferencing#page/n363/mode/2up | title=Microcomputer Color Graphics-Observations | magazine=[[Byte (magazine)|BYTE]] | date=December 1985 | access-date=28 October 2013 | last=Webster |first=Bruce | volume=10 |issue=13 | pages=405–418}}</ref> Introduced as the Macintosh Plus, it was the first [[Mac (computer)|Macintosh]] model to include a [[SCSI]] port, which launched the popularity of external SCSI devices for Macs, including hard disks, tape drives, CD-ROM drives, printers, [[Zip drive]]s, and even monitors.<ref>{{cite web|last1=Knight|first1=Daniel|title=ScuzzyGraph and ScuzzyGraph II|url=http://lowendmac.com/2013/scuzzygraph-and-scuzzygraph-ii/|website=Low End Mac|access-date=10 July 2015|date=24 March 2013|archive-date=July 11, 2015|archive-url=https://web.archive.org/web/20150711073521/http://lowendmac.com/2013/scuzzygraph-and-scuzzygraph-ii/|url-status=live}}</ref> The SCSI implementation of the Plus was engineered shortly before the initial SCSI spec was finalized and, as such, is not 100% SCSI-compliant. SCSI ports remained standard equipment for all Macs until the introduction of the [[iMac]] in 1998.

The Macintosh Plus was the last classic Mac to have an [[RJ11]] port on the front of the unit for the [[Apple Keyboard#Macintosh Plus Keyboard (M0110A)|keyboard]], as well as the [[DE-9]] connector for the [[Apple Mouse#Macintosh Mouse (M0100)|mouse]]; models released after the Macintosh Plus would use [[Apple Desktop Bus|ADB]] ports.

The Mac Plus was the first Apple computer to utilize user-upgradable [[SIMM]] memory modules instead of single [[Dual_in-line_package|DIP]] DRAM chips. Four SIMM slots were provided and the computer shipped with four 256 KB SIMMs, for 1 MB total RAM. By replacing them with 1 MB SIMMs, it was possible to have 4 MB of RAM. (Although 30-pin SIMMs could support up to 16 MB total RAM, the Mac Plus motherboard had only 22 address lines connected, for a 4 MB maximum.)

It has what was then a new {{frac|3|1|2}}-inch double-sided [[Macintosh External Disk Drive#800K|800 KB floppy drive]], offering double the capacity of [[floppy disk]]s from previous Macs, along with backward compatibility. The drive is controlled by the same [[Disk controller|IWM]] chip as in previous models, implementing [[Zone Bit Recording|variable speed]] [[Group Coded Recording|GCR]]. The drive was still completely incompatible with [[Personal computer|PC]] drives. The 800&nbsp;KB drive has two read/write heads, enabling it to simultaneously use both sides of the floppy disk and thereby double storage capacity. Like the 400&nbsp;KB drive before it, a companion [[Macintosh External Disk Drive#Macintosh 800K External Drive|Macintosh 800K External Drive]] was an available option. However, with the increased disk storage capacity combined with 2-4x the available RAM, the external drive was less of a necessity than it had been with the 128K and 512K.

The Mac Plus has 128&nbsp;KB of ROM on the motherboard, which is double the amount of ROM in previous Macs; the ROMs included software to support SCSI, the then-new 800&nbsp;KB floppy drive, and the [[Hierarchical File System (Apple)|Hierarchical File System]] (HFS), which uses a true directory structure on disks (as opposed to the earlier MFS, [[Macintosh File System]] in which all files were stored in a single directory, with one level of pseudo-folders overlaid on them). For programmers, the fourth ''[[Inside Macintosh]]'' volume details how to use HFS and the rest of the Mac Plus's new system software. The Plus still did not include provision for an internal hard drive and it would be over nine months before Apple would offer a SCSI [[Hard Disk 20SC|drive replacement]] for the slow Hard Disk 20. It would be well over a year before Apple would offer the first internal hard disk drive in any Macintosh.

A [[compact Macintosh|compact Mac]], the Plus has a {{convert|9|in|cm|adj=on}} 512 × 342 [[pixel]] monochrome display with a resolution of 72&nbsp;[[pixel density|PPI]], identical to that of previous Macintosh models.<ref name=plus-specs>{{cite web
| url = http://support.apple.com/kb/SP190
| title = Macintosh Plus: Technical Specifications
| publisher = Apple
| access-date = March 26, 2021
| archive-date = October 26, 2014
| archive-url = https://web.archive.org/web/20141026161117/https://support.apple.com/kb/SP190
| url-status = live
}}</ref>  Unlike earlier Macs, the Mac Plus's keyboard includes a numeric keypad and directional arrow keys and, as with previous Macs, it has a one-button mouse and no fan, making it extremely quiet in operation. The lack of a cooling fan in the Mac Plus led to frequent problems with overheating and hardware malfunctions.

The applications [[MacPaint]] and [[MacWrite]] were bundled with the Mac Plus. After August 1987, [[HyperCard]] and [[MultiFinder]] were also bundled. Third-party software applications available included [[MacDraw]], [[Microsoft Office Word|Microsoft Word]], [[Microsoft Excel|Excel]], and [[Microsoft PowerPoint|PowerPoint]], as well as [[Aldus PageMaker]]. Microsoft Excel and PowerPoint (originally by [[Forethought, Inc.|Forethought]]) were actually developed and released first for the Macintosh, and similarly Microsoft Word 1 for Macintosh was the first time a GUI version of that software was introduced on any personal computer platform. For a time, the exclusive availability of Excel and PageMaker on the Macintosh were noticeable drivers of sales for the platform.

[[File:Apple-Macintosh.jpg|thumb|250px|The Apple Macintosh Plus at the [[Röhsska Museum|Design Museum]] in [[Gothenburg]], [[Sweden]]]]

The case design is essentially identical to the original [[Macintosh 128K|Macintosh]]. It debuted in beige and was labeled ''Macintosh Plus'' on the front, but ''Macintosh Plus 1&nbsp;Mb'' on the back, to denote the 1&nbsp;MB RAM configuration with which it shipped. In January 1987 it transitioned to Apple's long-lived platinum-gray color with the rest of the Apple product line, and the keyboard's keycaps changed from brown to gray. In January 1988, with reduced RAM prices, Apple began shipping 2- and 4-&nbsp;MB configurations and rebranded it simply as "''Macintosh Plus''." Among other design changes, it included the same trademarked inlaid Apple logo and recessed port icons as the [[Apple IIc]] and [[Apple IIGS|IIGS]] before it, but it essentially retained the original design. On the inside of the case, embossed into it, are the signatures of all the people who worked on designing the Mac Plus, including Steve Jobs, Bill Atkinson, Andy Hertzfeld, Bruce Horn, Jef Raskin and the rest of the historic team.
<ref>{{cite web |last1=Rosen |first1=Adam |title=Signed by Steve Jobs & Co – Signatures Inside the Original Macintosh Case |url=https://www.cultofmac.com/122408/signed-by-steve-jobs-co-signatures-inside-the-original-macintosh-case/ |website=Cult of Mac |access-date=6 October 2022 |archive-date=October 6, 2022 |archive-url=https://web.archive.org/web/20221006154711/https://www.cultofmac.com/122408/signed-by-steve-jobs-co-signatures-inside-the-original-macintosh-case/ |url-status=live }}</ref>
[[File:Macintosh Plus interior 2.jpg|thumb|Inside a Macintosh Plus; the [[cathode-ray tube]] and its associated circuitry on  its right side take up a considerable amount of interior space.]]
{{Anchor|Upgrades}}An upgrade kit was offered for the earlier [[Macintosh 128K]] and [[Macintosh 512K]]/[[Macintosh 512Ke|''enhanced'']], which includes a new motherboard, floppy disk drive and rear case. The owner retained the front case, monitor and analog board. Because of this, there is no "Macintosh Plus" on the front of upgraded units, and the Apple logo is recessed and in the bottom left hand corner of the front case. However, the label on the back of the case reads "Macintosh Plus 1MB". The new extended Plus keyboard could also be purchased. Unfortunately, this upgrade cost almost as much as a new machine.

The Mac Plus itself can be upgraded further with the use of third-party accelerators. When these are clipped or soldered onto the 68000 processor, a 32&nbsp;MHz 68030 processor can be used, and up to 16&nbsp;MB RAM.<ref>{{cite web |url=http://lowendmac.com/1986/mac-plus/ |title=Mac Plus |publisher=Low End Mac |access-date=2016-05-20 |archive-date=March 24, 2018 |archive-url=https://web.archive.org/web/20180324010557/http://lowendmac.com/1986/mac-plus/ |url-status=live }}</ref>