GS/OS is an

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

developed by

Apple Computer Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company ...

for its Apple IIGS

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or te ...

. It provides facilities for accessing the

file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...

, controlling input/output devices, loading and running program files, and a system allowing programs to handle

interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, ...

s and signals. It uses

ProDOS ProDOS is the name of two similar operating systems for the Apple II series of personal computers. The original ProDOS, renamed ProDOS 8 in version 1.2, is the last official operating system usable by all 8-bit Apple II series computers, and w ...

as its primarily filing system. GS/OS is a component of Apple IIGS System Software versions 4.0 through 6.0.1, and was the first true 16-bit operating system for the IIGS.

Features

Speed optimization

The advantage of GS/OS over its predecessor, the ProDOS 16 operating system, is that it was written entirely in 16-bit code for the

65816 The W65C816S (also 65C816 or 65816) is an 8/16-bit microprocessor (MPU) developed and sold by the Western Design Center (WDC). Introduced in 1985, the W65C816S is an enhanced version of the WDC 65C02 8-bit computing, 8-bit MPU, itself a CMOS enha ...

processor used in the IIGS, rather than primarily in 8-bit

6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit microprocessor that was designed by a small te ...

machine code that does not take advantage of the IIGS's unique features. This in turn allows GS/OS to offers vast speed optimizations (loading time, disk access, screen updates) compared with the previous OS, and provided room to incorporates many features of other Apple operating systems, including

Apple III The Apple III (styled as apple ///) is a business-oriented personal computer produced by Apple Computer and released in 1980. Running the Apple SOS operating system, it was intended as the successor to the Apple II series, but was largely consi ...

Apple SOS, the Macintosh System 5, as well as concepts and features that would later appear in future Macintosh System Software releases (e.g. proportional scrollbars, thermometer progress bars)

New features and enhancements

In addition to continued enhancements to the IIGS Finder and loadable fonts, GS/OS offered plug-in device drivers (modem, printer, etc.), a thermometer progress display, AppleShare support, File System Translators for accessing foreign file formats, disk caching and support for storage devices up to 4 Gigabytes. It also extends the ProDOS file system to provide for

resource fork The resource fork is a fork or section of a file on Apple's classic Mac OS operating system, which was also carried over to the modern macOS for compatibility, used to store structured data along with the unstructured data stored within the data f ...

s on files similar to those used on the

Apple Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and software ...

, which allows for programs to be written in a more flexible way. The newly included Apple ''Advanced Disk Utilities'' and ''Apple IIGS Installer'' helped facilitate partitioning, formatting and installing software and drivers with visual ease. A command-line development environment called APW (Apple Programmer's Workshop) is available; much like the

Macintosh Programmer's Workshop Macintosh Programmer's Workshop (MPW) is a software development environment for the Classic Mac OS operating system, written by Apple Computer. For Macintosh developers, it was one of the primary tools for building applications for System 7.x an ...

File System Translators

GS/OS includes a unique facility known as file system translators (FSTs) which allows it to support multiple on-disk file systems in a manner transparent to application programs, a feature not found in ProDOS or most other microcomputer operating systems at the time. It was usually used with the ProDOS file system (which was the only one from which it could be booted), but GS/OS also supports a variety of other file systems, including the

Hierarchical File System Hierarchical File System (HFS) is a proprietary file system developed by Apple Inc. for use in computer systems running Mac OS. Originally designed for use on floppy and hard disks, it can also be found on read-only media such as CD-ROMs. HFS i ...

used by the

Mac OS Two major famlies of Mac operating systems were developed by Apple Inc. In 1984, Apple debuted the operating system that is now known as the "Classic" Mac OS with its release of the original Macintosh System Software. The system, rebranded "M ...

. Other file system translators, in addition to ProDOS and HFS, include those for

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few o ...

, High Sierra/ISO-9660, Apple DOS 3.3, and Pascal, albeit read-only (full read/write support had been planned but never completed).

Releases

Source:

ProDOS 16 (GS/OS predecessor)

*1986 – System 1.0 (ProDOS 16 v1.0), System 1.1 (ProDOS 16 v1.1) *1987 – System 2.0 (ProDOS 16 v1.2), System 3.1 (ProDOS 16 v1.3) *1988 – System 3.2 (ProDOS 16 v1.6)

GS/OS

*1988 – System 4.0 (GS/OS v2.0) *1989 – System 5.0 (GS/OS v3.0), System 5.0.1 (GS/OS v3.0), System 5.0.2 (GS/OS v3.0) *1990 – System 5.0.3 (GS/OS v3.03) *1991 – System 5.0.4 (GS/OS v3.03) *1992 – System 6.0 (GS/OS v4.01) *1993 – System 6.0.1 (GS/OS v4.02)

Unofficial versions

*2015 – System 6.0.2 (GS/OS v4.02), System 6.0.3 (GS/OS v4.02) *2017 – System 6.0.4 (GS/OS v4.02)

References

External links

Apple IIgs GS/OS 6.0.1 Screenshots and details

A2Central.com
– Apple II news and downloads {{DEFAULTSORT:GS OS Apple II software Apple Inc. operating systems Disk operating systems Discontinued operating systems Window-based operating systems