《Operating Systems Design and Implementation, 3/E》的笔记-第16页
- 页码：第16页 2011-02-27 21:32:47
1. The First Generation (1944-55) Vacuum Tubes and PlugboardsAround the mid-1940s, Howard Aiken, John von Neumann, J. Presper Eckert, John Mauchley and Konrad Zuse, among others, all succeeded in building calculating engines. The first ones used mechanical relays but were very slow. Relays were later replaced by vacuum tubes. In these early days, a single group of people designed, built, programmed, operated, and maintained each machine.Hardware: made of relays at first then the vacuum tubes insteadProgram language: absolute machine language written on plugboards at first then on the punched cards insteadPerformance: extremely slowUser requirement: straightforward numerical calculationsOs: none2. The Second Generation (1955-65) Transistors and Batch SystemsTransistors were introduced, and computers became reliable enough that they would continue to function long enough to get some useful work done. For the first time, there was a clear separation between designers, builders, operators, programmers, and maintenance personnel.A batch system was to collect a tray full of jobs, read them onto a magnetic tape using a small computer which was very good at reading cards, copying tapes, and printing output and much more expensive machines were used for real computing.Hardware: made of transistorsProgram language: FORTRAN or possibly even assembly language punched on cardsPerformance: time be saved using the batch systemUser requirement: scientific and engineering calculationsOs: FMS, IBSYS …3. The Third Generation (1965-1980) ICs and MultiprogrammingIBM introduced the System/360, which was a series of software-compatible machines and differed only in price and performance. The family had to be efficient for all of these different uses. Thus, the operating system had an enormous size and lots of bugs. OS/360 introduced some key techniques, such as multiprogramming and spooling (from Simultaneous Peripheral Operation On Line). The first serious timesharing system, CTSS (Compatible Time Sharing System), was developed at M.I.T. on a specially modified 7094. After the success of the CTSS system, MIT, Bell Labs, and General Electric decided to develop a machine that would support hundreds of simultaneous timesharing users, known as MULTICS (MULTiplexed Information and Computing Service). MULTICS introduced many seminal ideas such as distributed systems. Another major development during the third generation was the phenomenal growth of minicomputers. Ken Thompson wrote a stripped-down, one-user version of MULTICS, which later developed into the UNIX operating system.4. The Fourth Generation (1980-Present) Personal ComputersIntel came out with the 8080, the first general-purpose 8-bit microprocessor, in 1974, and the CP/M was widely used. Motorola also produced an 8-bit microprocessor, the 6800. A group of Motorola engineers left to manufacture the 6502 CPU. The Apple II, became a major competitor for CP/M systems.The next generation of microprocessors was 16-bit systems. Intel came out with the 8086, and in the early 1980s, IBM designed the IBM PC around Intel's 8088. Microsoft offered IBM a package which included Microsoft's BASIC and an operating system, DOS, whose revised system was renamed MS-DOS and quickly came to dominate the IBM PC market.Then, Doug Engelbart invented the GUI. Apple's Steve Jobs saw the possibility of a truly user-friendly personal computer and the Apple Macintosh wasannounced in early 1984, which supported the GUI. To compete with the Macintosh, Microsoft invented Windows. The other major contender in the personal computer world is UNIX. UNIX is strongest on workstations and other high-end computers.During the mid-1980s, there were a growing number of networks of personal computers running network operating systems and distributed operating systems. In a network operating system, the users are aware of the existence of multiple computers and can log in to remote machines and copy files from one machine to another. Basically, the machines are independent of one another. A distributed operating system, in contrast, is one that appears to its users as a traditional uniprocessor system, even though it is actually composed of multiple processors. The operations should all be handled automatically and efficiently by the operating system.5. The Relation of the Development of the Hardware and the OSIn the first generation, the computers were made of relays or vacuum tubes, and no operating system existed. And in the second generation, the transistors were introduced and simple operating systems came to the market. In the third generation, the ICs were invented, and then IBM introduced the OS/360. And the hardware allowed the key techniques (such as multiprogramming and spooling) of the OS run safely. Then the timesharing system CTSS came, but it did not really became popular until the necessary protection hardware became widespread. Then MULTICS was developed. The minicomputers were introduced. And then Ken Thompson wrote a stripped-down, one-user version of MULTICS, which later developed into the UNIX operating system. During the fourth generation, the LSI circuits were developed, so the age of the microprocessor-based personal computer dawned. And then with the development of the hardware, the GUI were realized and then there was a growth of networks of personal computers running the network OS and the distributed OS.From above, we can see that the development of OS relies on the hardware and the development if hardware can make ideas of the OS design become true.6. The Relation of the Performance, User Requirement and the Development of the OSFrom above, we can see that the performance is determined by the hardware, but a great design of OS can make full use of the hardware and improve the performance of the computer (such as the OS/360). The development of the OS is driven by the growing user requirement (such the GUI, the network OS and the distributed OS).
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