![mac plus computer mac plus computer](http://vintage-computer.com/images/Apple2Plus.jpg)
![mac plus computer mac plus computer](https://www.computercollection.net/wp-content/uploads/2019/08/IMG_5485-e1565623856424-768x1024.jpg)
This new filing system allowed it use the first hard drive Apple developed for the Macintosh 512K, the IWM floppy disk-based Hard Disk 20 and the new ROMs allowed the Macintosh to use the drive as a startup disk for the first time.
#Mac plus computer how to
For programmers, the fourth Inside Macintosh volume detailed how to use HFS and the rest of the Mac Plus's new system software.
#Mac plus computer software
It had 128 KB of ROM on the motherboard, which was double the amount of ROM that was in previous Macs the new System software and ROMs included routines to support SCSI, the new 800 KB floppy drive, and the Hierarchical File System (HFS), which used 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). It came standard with 1 MB of RAM (four 256 KB SIMMs) and could be upgraded to 4 MB of RAM. The Mac Plus was the first of many Macintoshes to use SIMMs (single in-line memory modules) for its memory.
![mac plus computer mac plus computer](http://www.vintagecomputer.net/apple/Macintosh_Plus/2_Macintosh_Plus_Computers.jpg)
The 800 KB drive had two read/write heads, enabling it to simultaneously use both sides of the floppy disk and thereby double storage capacity.
#Mac plus computer Pc
The drive was still completely incompatible with PC drives. The new drive was controlled by the same IWM chip as in previous models, implementing variable speed GCR. It had a new 3.5-inch double-sided 800 KB floppy drive, offering double the capacity of previous Macs along with backward compatibility. The Macintosh Plus was the last classic Mac to have a phone cord-like port in front for the keyboard, as well as the DE-9 connector for the mouse later models would use ADB ports. SCSI ports remained standard equipment for all Macs until the introduction of the iMac in 1998. As the Mac Plus had no provision at all for expansion other than the SCSI bus, the entire onus of expansion was on the user. Its SCSI implementation was engineered shortly before the initial SCSI spec was finalized and, as such, is not 100% SCSI-compliant. The Mac Plus 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. It originally had the same generally beige-colored case as the original Macintosh ("Pantone 453"), but in 1987, the case color was changed to the long-lived, warm gray "Platinum" color. As an evolutionary improvement over the 512K, it introduced RAM expansion from 1 MiB to 4 MiB, and the SCSI peripheral bus, among smaller improvements. The Macintosh Plus computer was the third model in the Macintosh line, introduced two years after the original Macintosh and a little more than a year after the Macintosh 512K.