System 7

from Wikipedia, the free encyclopedia
System 7
developer Apple Computer, Inc.
License (s) proprietary
Current  version 7.6.1 (April 7, 1997)
Kernel monolithic
ancestry Macintosh system software
Copland technology from Mac OS 7.6
Architecture (s) 68k , PowerPC (from 7.1.2)
timeline System 7
System 7.1
System 7.5
Mac OS 7.6
Languages) English, German and others

System 7 is an operating system from Apple and was released in June 1991. It derives directly from the Macintosh system software as it was first introduced on the first Apple Macintosh in 1984. The " System Software " Version 7 follows System 6 (also "Macintosh System Software 6") and is the first version, which was named Mac OS from January 1997, with Version 7.6 . System 7 is therefore often referred to retronymously as Mac OS 7 , although this is only correct from version 7.6.

System 7 is the only Macintosh operating system ever licensed for non-Apple computers, " Macintosh Clones ." The successor operating system Mac OS 8 appeared on July 26, 1997.

In the “Star Trek” project , System 7.1 was ported from Apple and Novell to IBM PC-compatible PCs, but not marketed.


The first ideas for System 7 came up with the completion of System 6 . In March 1988, developers and managers met for a brainstorming session on future operating system strategy. All the ideas for the operating system based on the current Macintosh system were written on blue index cards . This eventually became System 7 in the “ Blue Project ”. The development team itself was also associated with the color blue: they were called “ Blue Meanies ”, an ironic allusion to the “blue meanies”, the bad guys Beings in the Beatles film Yellow Submarine (film) .

System 7.0

System 7 was released in June 1991 and, like the previous versions of the Macintosh system software, is a pure single user system developed for Macintoshs with a 68k processor. Compared to previous versions, a hard drive was now necessary because the operating system could no longer be placed on a floppy disk . It requires at least 2 MB of RAM (around 1.2 MB more than System 6).

The Macintosh models Macintosh Plus , SE , SE / 30 , Classic , Portable , the entire Macintosh II series ( II , IIx , IIcx , IIci , IIfx , IIsi ) as well as Macintosh LC and LC II are officially supported . System 7.0.1 added support for the Macintosh Classic II , the Quadra models 500 and 900/950, and for the PowerBooks 100, 140, 145, 145B and 170.

The innovations of System 7 include 32-bit addressing on Macintosh models with a Motorola 68020 , 68030 or 68040 processor, which removes the 8 MB memory limit, cooperative multitasking , balloon help , virtual memory management , and QuickDraw 3D , TrueType support and TCP / IP .

On Macintosh computers with ROM that only supports 24-bit addressing, System 7 (as well as models with a Motorola 68000 processor) is still limited to 24-bits and thus to a maximum of 8 MB of RAM. For some Macs, with so-called " 32-bit dirty ROM," it was with the software MODE32 from Connectix still possible to use the 32-bit addressing mode. After protests by users, MODE32 was licensed by Apple and made available free of charge for the following Macintosh models: Macintosh II , IIx , IIcx and SE / 30 . All previous Macs were limited to 8 MB of memory, all newer Macs already offered a ROM, with the 32-bit memory access from home for work ( English 32-bit clean ROM ).

To maintain compatibility, however, virtual memory and 32-bit addressing can also be deactivated in System 7. After a restart, System 7 then runs in 24-bit mode, which causes some older Macintosh programs to cooperate. However, because the kernel has been rewritten, all applications that use undocumented functions of the Macintosh system software that were present up to System 6 will not run. However, most software manufacturers released updated versions of their programs, so very few Macintosh programs had such compatibility issues.

System 7.0 had an error, disappear the folder let ( english disappearing folders bug ). This error has been fixed with the tune-up update.

System 7.0.1 is made available for download by Apple free of charge.

System 7.1 and System 7 Pro

System 7.1 was the first Macintosh operating system that was no longer offered for free: in North America, it cost 79 US dollars to order directly from Apple. For the first time, there was also a standard version and a Pro version with additional software.

The innovations of System 7.1 are primarily of a technical nature. Fonts are now stored in their original state during installation in the new “Fonts” folder located in the system folder. The operating system can be made compatible with newer Macintosh models using so-called System Enablers . These were either preinstalled on the respective Macintosh model or they could be downloaded free of charge from Apple for specific models. In addition to “ System Enabler ”, “ PowerPC Enabler ” and “ PowerBook Enabler ” are also used, such as the “ PowerBook 150 Enabler ” for System 7.1 on the PowerBook 150. To make an installation compatible with a specific model, only the Enabler file needs to be used transferred from the system directory of an existing (previous) installation to the new installation or the free-of-charge downloaded enabler copied into the system directory. Older models, on the other hand, usually do not require a separate system enabler .

System 7.1P or 7.1P2 to 7.1P6 are model-specific versions for the Macintosh Performa with additional software, etc. a. Macintosh PC Exchange .

System 7 Pro is internally version 7.1.1 and came on 12 floppy disks. It contains the first versions of Apple Script and Power Talk (part of the A pple O pen C ollaboration E nvironment , AOCE) and QuickTime . The Finder is included in version 7.1.3 and offers full support for AppleScript. The additional software means that System 7 Pro now requires 5 MB of RAM, and even 8 MB for network functions.

System 7.1.2 was the first version that ran on PowerPC -based Macs. The PowerPC processor was intended to replace the Motorola 68k architecture and was jointly developed with IBM and Motorola based on IBM's POWER architecture. Both IBM and Motorola made the processors. However, since the operating system had already been developed for the Motorola 68030 and 68040, the PowerPC version of System 7 was based on a microkernel that could continue to execute 68k machine code in a transparent software emulation - with the disadvantage that this emulation had the speed advantage of the new PowerPC processor architecture destroyed.

The last update to System 7.1 is version 7.1.3, which was available as a free download from Apple.

With Star Trek , a port from System 7.1 to x86 processors should be implemented in 1992 . However, the project was discontinued in 1993 in favor of Copland .

Star Trek project

Novell had taken over DR DOS from Digital Research in 1991 and wanted to develop it further into a graphical PC operating system based on DOS as the operating system kernel and the graphical user interface GEM (or ViewMAX ). However, since Apple had already sued Digital Research because of GEM in 1985 , the Novell management was very keen to avoid another lawsuit by Apple. That is why Novell approached Apple in 1991 in order to jointly develop an operating system for the IBM PC that was competitive with Microsoft's Windows 3.0 . For its part, Apple had already toyed with the idea of ​​porting its own operating system to the IBM PC in the mid-1980s, but never implemented it. In 1991 the then CEO of Apple, John Sculley , thought the idea was good and agreed to Novell; Intel's CEO Andy Grove also showed interest in order not to be completely dependent on IBM and Microsoft (PC DOS / MS DOS and Windows, see Wintel ). From summer 1992 onwards, they worked together on porting the Apple operating system. Four Novell developers and 14 Apple developers were involved in the top secret project called “ Star Trek ”. In an office building in Santa Clara, across from Intel , each developer received their own office, a Macintosh and a 486 PC donated by Intel .

DR DOS "Panther" served as the basis. Building on this, System 7.1 was ported to the x86 architecture and DOS. After only three months, at the end of 1992, a stable prototype was ready, which was presented at Apple and Novell. Apple was astonished to see its own operating system running on the x86 hardware - until then it had been assumed that it would not be possible to run the operating system without the Macintosh Toolbox (the actual Macintosh API ), and this toolbox was thought to be difficult to transport. But the project was approved and development continued. The number of developers has been increased to 50.

At Apple, the biggest supporters of “Star Trek” were Vice President Roger Heinen and CEO John Sculley , but soon both left Apple. Roger Heinen was poached by Microsoft in 1992 and John Sculley was succeeded as CEO shortly afterwards by Michael Spindler in 1993 . At the same time, Apple entered into a cooperation with IBM and Motorola in 1992 to introduce a new processor architecture. By based on IBM's POWER PowerPC should Motorola 680x0 be replaced. The processor itself was to be manufactured by both IBM and Motorola. Therefore, Apple viewed the matter critically, on the one hand bringing a PC-x86 operating system onto the market, which on the other hand would be in direct competition with the Macintosh and thus also with the PowerPC.

There were also increasing problems on the PC side. One of the “Star Trek” developers, Mark Gonzales, was originally of the opinion that there was a profitable market for a PC-System-7, but when the operating system began to be shown to various PC manufacturers in 1993, they were unwilling to pay for the operating system. The reason for this was that the manufacturers were bound by a contract with Microsoft to pay a certain amount to Microsoft for every computer that was sold - regardless of which operating system was actually installed. The PC manufacturers would have had to pay twice - or offer Apple "Star Trek" for free, which would have undermined the market for the Macintosh twice.

After Michael Spindler had made it his task to make Apple, which was in crisis, competitive again after he took up his position as CEO, he prescribed a rigorous austerity program for the entire company - which in June 1993 also meant the end of "Star Trek".

At a developer meeting in 1997, the project was demonstrated again: After a few attempts, “Star Trek” could be started on a PC. The text “ Star Trek: Boldly Going Where No Mac Has Gone Before. “- an allusion to spaceship Enterprise , the introduction of which says:“ ... where no man has been before ” (“  English where no man has gone before ”). The developers were consistently of the opinion that System 7 would have had a real chance on PCs and would probably have been available a year before the great Microsoft success Windows 95 would have been available.

Technical implementation with DR DOS

In order to port System 7.1 to the Intel x86 platform, the DR DOS from Digital Research, which Novell had bought up a year earlier, was used, which already ran stably and including multi-tasking on x86 PCs. This DR DOS "Panther" - a further development of DR DOS 6.0 - was adapted by Novell's developers while the Apple developers were working on the porting of System 7. The Apple operating system was partly written in m68k - assembler , close to the hardware, which meant speed advantages and leaner programs on Macintosh hardware. However, these parts now had to be rewritten for the x86 architecture. Other parts of System 7 were written in Pascal and only had to be modified and recompiled slightly.

On Macintosh computers, parts of the operating system were built into the Macintosh ROM . That made sense in the 1980s as ROM was cheaper and faster than RAM at the time . An additional advantage was that the operating system could not run without the ROM, which made it almost impossible to use the Macintosh system software on other hardware without obtaining (licensing) the ROM directly from Apple. When porting to Intel x86 PCs, however, it appeared to the developers as too cumbersome and expensive to integrate the ROM as hardware in the PC, so the functions of the Macintosh Toolbox from the ROM instead, during the startup of system 7 as software in the memory has been loaded. Such a technique was developed by Apple later with a " New World acquired Macs designated" (German "New World"): the iMac in 1998 was the first Mac, the Macintosh ROM and toolbox contained from the classic Mac OS contained Loads file Mac OS ROMfrom hard disk into RAM.

Through the easy portability of Pascal source code already running on the prototype of "Star Trek" next to the Finder and QuickDraw GX and QuickTime . Macintosh programs from third-party manufacturers would have had to be adapted to the x86 architecture and System 7 to x86 - here too, either with minor changes to the source code for languages ​​such as Pascal and C , but with considerable effort for the m68k assembler. Many manufacturers used lean and fast m68k assembler to optimize and increase the speed of their Macintosh programs.

As the core of the operating system is a further development of DR-DOS 6.0 was used, which was present at Novell already under the developer name "Panther": The core was protected mode - Task Manager "Vladivar" that already Preemptive multitasking supported. "Vladivar" was developed out of Multiuser DOS (from Digital Research). Furthermore, "Panther" supported DPMS , multi-user - permissions (world / group / owner, similar to the classes of users of Unix file permissions ) and included with ViewMAX / 3 one with Windows 3.0 similar graphical user interface. With DR DOS "Panther" Beta 1 of October 16, 1992, DR DOS proves to be API-compatible with PC DOS 5 for the first time. A system call of the BDOS kernel can be used to read out the version number that 1070houtputs the value for “Panther” : that 10hstands for single-user DOS and that 70h( hexadecimal , but not interpreted as a decimal number) for BDOS version number 7.0. For comparison: the finished DR DOS 6.0 from 1991 reported API compatibility with IBM DOS 3.31 and version number 1067h(single user, BDOS 6.7). DR DOS “Panther” itself remained unpublished, but some of the improvements were incorporated into later versions: from “business update” or patch “DRDOS493”, DR DOS 6.0 version 1071h(BDOS 7.1) and Novell DOS 7 1072h(BDOS 7.2) reported.

The exact version of DR DOS “Panther” for “Star Trek” is not known, but probably BDOS 7.0. The special adjustments for System 7.1 included an HFS and Mac emulation layer for the FAT file system.

Macintosh clones

From December 1994, under the leadership of CEO Michael Spindler , Apple decided on the “clone program”: For the first time in Apple's history, the company was ready to sell licenses for the Macintosh operating system. Macintosh clones had already existed in the 1980s, but these relied on the ROM of an original donor Macintosh, as Apple did not sell the ROM alone.

Fast a market for Macintosh clones, established English Macintosh clones . Rather than being clones of a Macintosh, these were PC's compatible with System 7, and could offer the same computing power at cheaper prices. 1995 was the year Microsoft broke all sales records with Windows 95 . System 7 from Apple, on the other hand, was out of date despite 32-bit technology, as it still only offered cooperative multitasking and no memory protection. If Apple had previously hoped to boost Macintosh and System 7 sales with the help of licensed clones, now the legal clones fished in the market for their own Macintosh computers, and sales also plummeted.

Companies that made Macintosh clones included a. Radius, Power Computing, DayStar Digital, Umax SuperMac and Motorola StarMax.

Apple's sales dropped from 4.5 million Macs sold in 1995 to 2.8 million in 1997. In January 1996, Gil Amelio became Apple's new CEO, and in late 1996 NeXT was acquired and Steve Jobs returned to Apple. Jobs became Apple's CEO in July 1997. He finally renegotiated the license payments with the clone manufacturers, which meant higher fees for them and thus made up for the price advantage of the clones compared to the original Apple Macs. In the end, however, Steve Jobs took advantage of the specific contractual terms for the clone program that only System 7 licensed - in order to terminate the program without committing a breach of contract, Mac OS was not released under version 7.7, but as version 8.0 , which was released by the clone manufacturers could not be distributed preinstalled.

The market for Macintosh clones finally ended because the manufacturers saw no future in it: even in the times of Mac OS 8, Mac OS 8.5 and Mac OS 9, they could only have offered systems with System 7 or Mac OS 7. However, as most Macintosh clone users have found, Mac OS 8 will run fine on most clones. Some even running Mac OS 8.5 and Mac OS 9 and a hacked version of Mac OS X .

Copland project

Because System 7 and System 7.1 were and were considered out of date in the mid-1990s, Apple was working on a successor operating system with the project name "Copland". Together with the second phase, project name "Gershwin," the finished operating system was planned as "System 8," later as "Mac OS 8,".

The problem with System 7 was not only the lack of preemptive multitasking and memory protection, rather System 7 was a pure Motorola 68k operating system. In order to run on PowerPC systems at all, a microkernel with a transparent 68k emulation layer was a solution. Fast PowerPC Macintosh models had now been released, but with System 7.1.2 and later they didn't feel much faster than their predecessors with a 68k processor because the necessary emulation undermined the faster execution speed.

System 7 should have been written from scratch for the PowerPC architecture, which would have taken several years. Because then there would still have been no real multitasking and no memory protection, Apple started developing a successor operating system instead: Copland (+ Gershwin) = System 8.

In March 1994, work began on Copland. In 1996 the finished operating system should have appeared. When Copland ("Mac OS 8," not identical to the later Mac OS 8) was still not finished in 1997, the project was canceled. Some of the extensions intended for Copland (OpenDoc, QuickDraw GX) have already been included in System 7.5 in preparation. Parts from Copland were integrated into Mac OS 7.6, Mac OS 8 and newer after the end of the project, but the kernel and the core architecture initially remained unchanged.

System 7.5

System 7.5 was again offered free of charge by Apple, or for a smaller cost of 35 US dollars, diskettes could be ordered directly from Apple. The concept of standard and pro versions, as introduced in System 7.1, has been dropped: all additional programs from System 7 Pro are now available for System 7.5. System 7.5.3 can be downloaded for free from Apple. In 2013, however, the directory listings disappeared, so you now have to know the exact link to download the diskette images.

The new features include the interactive help “Apple Guide,” “Desktop Printing” and the “Extensions Manager.” In addition, System 7.5 now includes QuickTime 2.5, which is faster and offers additional codecs . With OpenTransport, improved network software was introduced to replace MacTCP. Further improvements concern the Finder, which can now find a suitable application for unknown file types ("Macintosh Easy Open"), an improved "Sound Manager," improved drag and drop ("Macintosh Drag and Drop") and integrated CD-ROM -Support (which eliminates the need to install additional drivers). For the first time, ColorSync is also included.

The Motorola 68k emulation, which should be faster as of System 7.5, has also been improved. However, all new features come at a price: the system now occupies almost 3 MB of RAM after booting. If additional updates and applications are installed, 4 MB of working memory can be reached quickly just through the operating system. A full installation including additional applications and drivers also takes up 200 MB on the hard drive.

When System 7.5 was released, Copland development was in full swing. So it's not surprising that technologies that were actually developed for Copland also found their way into System 7.5: OpenDoc and QuickDraw GX .

As of System 7.5.1, the new Mac OS logo is used in the start screen instead of the familiar Happy Mac .

System 7.5.3 Revision 2 including System Update 2.0 is made available for download by Apple free of charge.

Mac OS 7.6

Starting with version 7.6 (January 1997) the operating system was officially renamed Mac OS . The reason for this change were licensed Macintosh clones , on which the name change was intended to indicate Macintosh and Apple more clearly than before.

Like System 7.1 before, Mac OS 7.6 was no longer offered for free. It was $ 99 at Apple in North America.

Mac OS 7.6 requires a 32-bit Mac with at least a Motorola 68030 processor, 8 MB of RAM and 70 MB of free hard disk space; 16 MB of RAM and 120 MB of free hard disk space are recommended.

In contrast to System 7.5.5, Mac OS 7.6 no longer runs in 24-bit mode. As a direct consequence, Macintosh computers with a Motorola 68000/68020 processor and Macs with “24-bit dirty ROM” are no longer supported - older programs that require the 24-bit addressing mode can no longer be executed.

The last update for System 7 was version 7.6.1 in April 1997.

Mac OS 7.7

The Macintosh clones (“ Mac clones ”) are due to the fact that version 7.7 already appeared as Mac OS 8.0 : Due to the contract with Apple, only System 7 could be sold on the clones. With the takeover of NeXT in late 1996 and the paradigm shift within Apple, the cloning program was discontinued.

There is a leaked beta version of Mac OS 7.7, codenamed “Speedy”, which had already adopted the look of Copland in the form of the “Appearance Manager”. When it was released, the operating system was finally called Mac OS 8.0, code name “Tempo”. The name was previously used by Copland, which was announced in its last development version as the upcoming "Mac OS 8", but never appeared. Mac OS 8 is therefore not Copland, because technically speaking, Mac OS 8.0 ("Tempo", alias Mac OS 7.7 "Speedy") is very similar to the previous version Mac OS 7.6. But Apple is continuing the transfer of usable Copland technology into the classic Mac OS, which began with Mac OS 7.6.


Surname version Publication date Code name Remarks
system Older version; no longer supported: 7th June 1991 Blue, Big Bang, M80, Pleiades
Older version; no longer supported: 7 tune-up 7-Up
Older version; no longer supported: 7.0.1 October 21, 1991 Road warrior specific version for the PowerBook 140
Older version; no longer supported: 7.0.1 1991 Beta cheese
Older version; no longer supported: 7.1 Cube-E, I Tripoli
Older version; no longer supported: 7.1 Pro Jirocho
Older version; no longer supported: 7.1.1
Older version; no longer supported: 7.1.2 first PowerPC version
Older version; no longer supported: 7.1.3 1994 Version 7.1.3 is the last update of System 7.1 and could be downloaded for free from Apple as "System Update 3.0".
Older version; no longer supported: 7.5 September 1994 Mozart, Capone
Older version; no longer supported: 7.5 Update 1.0 March 1995 Danook This version mainly fixes bugs. After applying "System Update 1.0" to System 7.5, it appears as System 7.5.1. The startup logo is new in this version.
Older version; no longer supported: 7.5.1
Older version; no longer supported: 7.5.2 Marconi System 7.5.2 is considered to be very unstable. There was also support for Macintosh computers with a PCI bus and the new "Open Transport" network architecture.
Older version; no longer supported: 7.5 Update 2.0 January 1996 Thag System 7.5.3 combined all model-specific versions of System 7.5 into a single update package and fixed the bugs that made the previous version so unstable. In addition, the transparent 68k emulation layer and the "Drag Manager" have been improved. After applying "System Update 2.0", System 7 presents itself as version 7.5.3.
Older version; no longer supported: 7.5.3 Unity
Older version; no longer supported: 7.5.3 Revision 1 1996 Buster
Older version; no longer supported: 7.5.3 Revision 2 March 11, 1996 Son of Buster This version was also sold on CD-ROM and can also be downloaded for free from Apple. The update was known as "System 7.5 Update 2.0 Revision 2".
Older version; no longer supported: 7.5.4 1996 System 7.5.4 was an update to System 7.5.3, but it contained a bug in IRTalk for Power Mac 5400 and 6400 and was therefore withdrawn shortly after its release.
Older version; no longer supported: 7.5.5 September 18, 1996 System 7.5.5 is a free (free) update for System 7.5 and was released shortly after version 7.5.4, but this time with no errors in the installation package. Only a 7.5.3 system that has already been installed can be updated.
Mac OS Older version; no longer supported: 7.6 January 1997 Harmony
Older version; no longer supported: 7.6.1 April 1997 Ides of buster
Old version
Older version; still supported
Current version
Current preliminary version
Future version

For a long time, System 7.0.1 and System 7.5.3 were available for free download from Apple with the upgrade to System 7.5.5. System 7.1 and Mac OS 7.6 had to be paid for, and their updates were also available free of charge. At the end of 2013, Apple removed the directory catalog, so entering a completely correct URL is necessary. To do this, you have to know both the exact HTTP address and the exact file names.

Web links

Individual evidence

  1. Amit Singh: Mac OS X Internals . A systems approach. 1st edition. Addison-Wesley Professional, 2006, ISBN 0-321-27854-2 , Ch. 1: Origins of Mac OS X, pp. 2 , Apple's Quest for the 2 Operating System (English, limited preview in Google Book Search [accessed January 4, 2017]).
  2. a b c d Tyler Sable: System 7: Bigger, Better, More Expandable, and a Bit Slower than System 6 . LowEndMac, June 25, 2014 (English); Retrieved April 4, 2016.
  3. Apple: System Software: Version Matrix, System 6.0.x to 7.0.1 (English); accessed on April 23, 2016.
  4. D-7.0.1.txt , accessed on September 14, 2016; The files are named D-7.0.1-Disk_Tools.image.sea.bin, D-7.0.1-Fonts.image.sea.bin, D-7.0.1-Install_1.image.sea.bin, D-7.0.1-Install_2.image.sea.bin, D-7.0.1-Printing.image.sea.binand D-7.0.1-Tidbits.image.sea.bin.
  5. The Mac 512: System Software Download Section ( Memento of the original from April 7, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (English); accessed on April 23, 2016. @1@ 2Template: Webachiv / IABot /
  6. a b Mark H. Anbinder: System 7 Pro Ships. TidBITS, October 11, 1993, accessed January 4, 2017 : "Apple released System 7.1 last October with a new policy requiring users to purchase an upgrade, unless they received the software with a new Macintosh, thus ending their long history of free upgrades for existing users. This time Apple has decided to support two separate levels of System software: a standard version which will still be called 'System 7,' and a more fully-featured version dubbed 'System 7 Pro.' "
  7. Sebastian Kempgen: MacCampus® Macintosh Font Basics. (PDF; 197 kB) MacCampus® Cornelia Kempgen, October 1995, p. 19 , accessed on January 4, 2017 : “As of System 7.1, a new folder within the system folder contains all components of any font: the folder 'Fonts.' Suitcases of any content (bitmap fonts, TrueType fonts, screen fonts from PostScript character sets) and all associated printer fonts belong in it. With this type of installation, the character set suitcase remains as it was placed in it (under 7.0 they were broken down into their components and dissolved). "
  8. System 7.1 through Mac OS 7.6: Compatibility With Macintosh Computers Apple (English); accessed on April 23, 2016.
  9. System version numbering history. (No longer available online.) The Mac 512, archived from the original on December 2, 2016 ; accessed on January 4, 2017 (English). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  10. System 7 pro. Computer History Museum, accessed January 4, 2017 .
  11. a b c Tom Hormby: Star Trek: Apple's First Mac OS on Intel Project . LowEndMac, April 27, 2014 (English); accessed on April 15, 2016.
  12. Owen W. Linzmayer: Apple Confidential 2.0: The Definitive History of the World's Most Colorful Company . No Starch Press, San Francisco 2004, ISBN 1-59327-010-0 , The Star Trek Saga, pp. 229–232 ( [accessed December 6, 2015]).
  13. a b Jodi Mardesich: The secret weapon Apple threw away . November 1, 1997
  14. 25 Years of DR DOS History . (English)
  15. Dan Knight: Apple Macintosh clone Squeezes Out of the Market . LowEndMac, January 25, 2014 (English); Retrieved April 24, 2016.
  16. ^ The Long View - Copland (English), basalgangster, February 26, 2011; Retrieved April 24, 2016.
  17. D-System_7.5.3_Info.txt , accessed on September 14, 2016; the floppy disks have the file name D-System_7.5.3-01of17.smi.binor from diskette no. 2.D-System_7.5.3-02of17.part.bin
  18. ^ Discussion forum of the Association for the Preservation of Classical Computers e. V .: Download German System 7.5.x version - where? , December 20, 2013; accessed on April 23, 2016. At the end of 2013, Apple took the free (free) older “classic” Macintosh software offline.
  19. a b c d e f g h System 7.5 and Mac OS 7.6: The Beginning and End of an Era . LowEndMac (English); accessed on April 23, 2016.
  20. Classic Mac OS Downloads and Updates . LowEndMac (English); Retrieved April 29, 2016.
  21. Peter Brockie: System 7.7a2c5 (code name: “Speedy”) . ( Memento of the original from November 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (English); accessed on April 23, 2016. @1@ 2Template: Webachiv / IABot /
  22. ^ Andy F. Mesa : Apple Code Names - Mac OS . The Apple Museum (English); accessed on March 29, 2016.
  23. a b c d e f Apple Updates (Classic Mac OS). Pure Mac (English); accessed on April 23, 2016.