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The Macintosh Plus computer is the third model in the Macintosh line, introduced on January 16, 1986, two years after the original Macintosh and a little more than a year after the Macintosh 512K, with a price tag of US$2599.〔http://www.pcworld.com/article/126692-9/the_25_greatest_pcs_of_all_time.html〕 As an evolutionary improvement over the 512K, it shipped with 1 MB of RAM standard, expandable to 4 MB, and an external SCSI peripheral bus, among smaller improvements. It originally had the same generally beige-colored case as the original Macintosh ("Pantone 453"〔(History of computer design: Apple Macintosh )〕), but in 1987, the case color was changed to the long-lived, warm gray "Platinum" color.〔(History of computer design: Macintosh Plus )〕 It is the earliest Macintosh model able to run System 7 OS. == Overview == Introduced as the ''Macintosh Plus'', it was the first 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, and even monitors. 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, which replaced most of Apple's legacy ports with USB. The Macintosh Plus was the last classic Mac to have a phone cord-like port on the front of the unit for the keyboard, as well as the DE-9 connector for the mouse; models released after the Macintosh Plus would use ADB ports. It has what was then a new 3.5-inch double-sided 800 KB floppy drive, offering double the capacity of floppy disks for previous Macs, along with backward compatibility. The then-new drive is controlled by the same IWM chip as in previous models, implementing variable speed GCR. The drive was still completely incompatible with PC drives. The 800 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 KB drive before it, a companion Macintosh 800K External Drive was an available option. However, with the increased 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 was the first of many Macintoshes to use SIMMs (single in-line memory modules) for its memory. It came standard with 1 MB of RAM (four 256 KB SIMMs) and could be upgraded to 4 MB of RAM. It has 128 KB of ROM on the motherboard, which is double the amount of ROM that's in previous Macs; the then-new System software and ROMs included routines to support SCSI, the then-new 800 KB floppy drive, and the 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. This new filing system allows it to use the first hard drive Apple developed for the 512K, the IWM floppy disk-based Hard Disk 20 and the then-new ROMs allow the Macintosh to use the drive as a startup disk for the first time. 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 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 Mac, the Plus has a 512×342 pixel monochrome display with a resolution of 72 PPI, identical to that of previous Macintosh models. 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 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 Word, Excel, and PowerPoint, as well as Aldus's PageMaker. Microsoft Excel and PowerPoint (originally by 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. The case design is essentially identical to the original Macintosh. It debuted in beige and was labeled ''Macintosh Plus'' on the front, but ''Macintosh Plus 1 MB'' on the back, to denote the 1 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- 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 IIGS before it, but it essentially retained the original design. An upgrade kit was offered for the earlier Macintosh 128K and Macintosh 512K/''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 MHz 68030 processor can be used, and up to 16 MB RAM. This allows it to run Mac OS 7.6.1.〔(Macintosh Plus Profile )〕 There is a program available called Mini vMac that can emulate a Mac Plus on a variety of platforms, including Unix, Windows, DOS, Mac OS, Mac OS X, Pocket PC, iOS (on jailbroken devices) and even Nintendo DS. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Macintosh Plus」の詳細全文を読む スポンサード リンク
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