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Motorola 68851
The Motorola 68851 is an external Memory Management Unit (MMU) which is designed to provide paged memory support for the 68020 using that processor's coprocessor interface. In theory it can be used with other processors such as the 68010 by simulating the coprocessor interface in software. Later 68K family processors such as the 68030, 68040, and 68060 have an internal MMU, and will not operate with the 68851, except possibly by simulation of the coprocessor interface. The 68851 was available as an option for the Apple Macintosh II, and was necessary to run Apple's A/UX operating system. On the classic Mac OS, Connectix Virtual was released in early 1989 and used the 68851 to provide virtual memory, which was later integrated into System 7. Very few cards for the Amiga make use of the 68851 primarily because it can only be used with a small range of processors and most Amigas and accelerator cards use a processor which either has its own MMU or cannot support an MMU. One of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motorola 68851 Die
Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been radio-related communication equipment such as two-way radios, consumer walkie-talkies, cellular infrastructure, mobile phones, satellite communicators, pagers, as well as cable modems and semiconductors. After having lost $4.3 billion from 2007 to 2009, Motorola was split into two independent public companies: Motorola Solutions (its legal successor) and Motorola Mobility (spun off), on January 4, 2011. Motorola designed and sold wireless network equipment such as cellular transmission base stations and signal amplifiers. Its business and government customers consisted mainly of wireless voice and broadband systems (used to build private networks), and public safety communications systems like Astro and Dimetra. Motorola's home and broad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Management Unit
A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit that examines all references to computer memory, memory, and translates the memory addresses being referenced, known as virtual memory addresses, into physical addresses in main memory. In modern systems, programs generally have addresses that access the theoretical maximum memory of the computer architecture, 32 or 64 bits. The MMU maps the addresses from each program into separate areas in physical memory, which is generally much smaller than the theoretical maximum. This is possible because programs rarely use large amounts of memory at any one time. Most modern operating systems (OS) work in concert with an MMU to provide virtual memory (VM) support. The MMU tracks memory use in fixed-size blocks known as ''pages''. If a program refers to a location in a page that is not in physical memory, the MMU sends an interrupt to the operating system. The OS selects a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
68020
The Motorola 68020 is a 32-bit microprocessor from Motorola, released in 1984. A lower-cost version was also made available, known as the 68EC020. In keeping with naming practices common to Motorola designs, the 68020 is usually referred to as the "020", pronounced "oh-two-oh" or "oh-twenty". The 020 was in the market for a relatively short time. The Motorola 68030 was announced in September 1986 and began deliveries in the summer of 1987. Priced about the same as the 020 of the time, the 030 was significantly faster and quickly replaced in 020 in almost every use. History 68000 and 68010 At the time the Motorola 68000 was designed, Motorola's design and fabrication services were outdated. Although even small companies like MOS Technology and Zilog had moved on to silicon gate depletion mode NMOS logic on ever-larger wafers, Motorola was still using metal gates and enhancement mode and their largest fab worked on 4-inch wafers long after most lines had moved to 5-inch. Although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
68010
The Motorola MC68010 and Motorola MC68012 are 16/32-bit microprocessors from Motorola, released in 1982 as successors to the Motorola 68000. The 68010 and 68012 added virtualization features, optimized loops and fixed several small flaws to the 68000. The MC68010 variants were pin compatible with its predecessor while the MC68012 is an 84-pin PGA version with its directly accessible memory space extended to 2 GiB. Differences between 68010/68012 and 68000 The 68010 and 68012 are completely user-mode compatible with the 68000, except that the MOVE from SR instruction traps in user mode, so that, to support user-mode code using that instruction, a supervisor-mode trap handler must simulate the instruction and continue the user-mode code after that instruction. This was done so that the 68010 and 68012 would meet the Popek and Goldberg virtualization requirements, specifically that a new OS could run as guest and not be aware. A new unprivileged MOVE from CCR instruction w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
68030
The Motorola 68030 ("''sixty-eight-oh-thirty''") is a 32-bit microprocessor in the Motorola 68000 family. It was released in 1987. The 68030 was the successor to the Motorola 68020, and was followed by the Motorola 68040. In keeping with general Motorola naming, this CPU is often referred to as the 030 (pronounced ''oh-three-oh'' or ''oh-thirty''). The 68030 is essentially a 68020 with a memory management unit (MMU) and instruction and data caches of 256 bytes each. It added a burst mode for the caches, where four longwords can be loaded into the cache in a single operation. The MMU was mostly compatible with the external 68851 that would be used with the 68020, but being internal allowed it to access memory one cycle faster than a 68020/68851 combo. The 68030 did not include a built-in floating-point unit (FPU), and was generally used with the 68881 and the faster 68882. The addition of the FPU was a major design note of the subsequent 68040. The 68030 typically incr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
68040
The Motorola 68040 ("''sixty-eight-oh-forty''") is a 32-bit microprocessor in the Motorola 68000 series, released in 1990. It is the successor to the 68030 and is followed by the 68060, skipping the 68050. In keeping with general Motorola naming, the 68040 is often referred to as simply the '040 (pronounced ''oh-four-oh'' or ''oh-forty''). The 68040 was the first 680x0 family member with an on-chip Floating-Point Unit (FPU). It thus included all of the functionality that previously required external chips, namely the FPU and Memory Management Unit (MMU), which was added in the 68030. It also had split instruction and data caches of 4 kilobytes each. It was fully pipelined, with six stages. Versions of the 68040 were created for specific market segments, including the 68LC040, which removed the FPU, and the 68EC040, which removed both the FPU and MMU. Motorola had intended the EC variant for embedded use, but embedded processors during the 68040's time did not need the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
68060
The Motorola 68060 ("''sixty-eight-oh-sixty''") is a 32-bit microprocessor from Motorola released in April 1994. It is the successor to the Motorola 68040 and is the highest performing member of the 68000 series. The 68060 is the last development of the 68000 family for general purpose use, abandoned in favor of the PowerPC chips. Two derivatives were produced, the 68LC060 (low cost) which lacked the floating point unit (FPU) and the 68EC060 (embedded controller) which removed both the FPU and memory management unit (MMU). Architecture There is an LC (Low-Cost) version, without an FPU and EC (Embedded Controller), without MMU and FPU. The 68060 design was led by Joe Circello. The 68060 shares most architectural features with the P5 Pentium. Both have a very similar superscalar in-order dual instruction pipeline configuration, and an instruction decoder which breaks down complex instructions into simpler ones before execution, described publicly as "two four-stage RISC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macintosh II
The Macintosh II is a personal computer designed, manufactured, and sold by Apple Computer from March 1987 to January 1990. Based on the Motorola 68020 32-bit CPU, it is the first Macintosh supporting color graphics. When introduced, a basic system with monitor and 20 MB hard drive cost . With a 13-inch color monitor and 8-bit display card, the price was about . This placed it in competition with workstations from Silicon Graphics, Sun Microsystems, and Hewlett-Packard. The Macintosh II was the first computer in the Macintosh line without a built-in display; a monitor rested on top of the case like the IBM Personal Computer and Amiga 1000. It was designed by hardware engineers Michael Dhuey (computer) and Brian Berkeley (monitor) and industrial designer Hartmut Esslinger (case). Eighteen months after its introduction, the Macintosh II was updated with a more powerful CPU and sold as the Macintosh IIx. In early 1989, the more compact Macintosh IIcx was introduced at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A/UX
A/UX is a Unix-based operating system from Apple Computer for Macintosh computers, integrated with System 7's graphical interface and application compatibility. It is Apple's first official Unix-based operating system, launched in 1988 and discontinued in 1995 with version 3.1.1. A/UX requires select 68k-based Macintosh models with an FPU and a paged memory management unit (PMMU). Its foundation is UNIX System V Release 2.2, with features from Releases 3 and 4 and from BSD versions 4.2 and 4.3. It is compliant with POSIX and System V Interface Definition (SVID), and includes TCP/IP networking since version 2. Having a Unix-compatible, POSIX-compliant operating system enabled Apple to bid for large contracts to supply computers to the U.S. federal government. A/UX was described by '' MacUser'' as "the most interesting and impressive software to have come out of Apple since HyperCard" and by ''InfoWorld'' as "an open systems solution with the Macintosh at its heart". Feature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classic Mac OS
Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Mac (computer), Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and ending with Mac OS 9. The Macintosh operating system is credited with having popularized the graphical user interface concept. It was included with every Macintosh that was sold during the era in which it was developed, and many updates to the system software were done in conjunction with the introduction of new Macintosh systems. Apple released the Macintosh 128K, original Macintosh on January 24, 1984. The System 1, first version of the system software, which had no official name, was partially based on the Lisa OS, which Apple previously released for the Apple Lisa, Lisa computer in 1983. As part of an agreement allowing Xerox to buy Share (finance), shares in Apple at a favorable price, it also used concepts from the PARC (company), Xerox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connectix
Connectix Corporation was a software and hardware company that released innovative products that were either made obsolete as Apple Computer incorporated the ideas into system software, or were sold to other companies once they became popular. It was formed in October 1988 by Jon Garber; the dominant board members and co-founders were Garber, Bonnie Fought (the two were later married), and close friend Roy McDonald. McDonald was still Chief Executive Officer and president when Connectix finally closed in August 2003. Products Primary products included these: * Virtual: Its original flagship product, which introduced virtual memory to the Macintosh operating system, Classic Mac OS, Mac OS, years before Apple's implementation in System 7. Virtual also runs on a motley assortment of accelerator cards for the original Mac, Mac Plus, and Mac SE, which were not supported by Apple. * HandOff II: The file launcher developed by Fred Hollander of Utilitron, Inc. This INIT for Macintosh s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System 7
System 7 (later named Mac OS 7) is the seventh major release of the classic Mac OS operating system for Macintosh computers, made by Apple Computer. It was launched on May 13, 1991, to succeed System 6 with virtual memory, personal file sharing, QuickTime, TrueType fonts, the Force Quit dialog, and an improved user interface. It was code-named "Big Bang" in development and the initial release was named "The System" or "System" like all earlier versions. With version 7.5.1, the name "Mac OS" debuted on the boot screen, and the operating system was officially renamed to Mac OS in 1997 with version 7.6. The Mac OS 7 line was the longest-lasting major version of the Classic Mac OSes due to the troubled development of Copland, an operating system intended to be the successor to OS 7 before its cancellation and replacement with Mac OS 8. Development By 1988, the Macintosh had been on the market for four years. Some aspects of the operating system were beginning to fall behind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
