AMIGA-os

The Commodore Amiga was released in 1985, and was among the first (and certainly most successful) home computers to feature a microkernel operating system. The Amiga's kernel, exec.library, was small but capable, providing fast pre-emptive multitasking on similar hardware to the cooperatively-multitasked Apple Macintosh, and an advanced dynamic linking system that allowed for easy expansion

XENIX

Xenix is a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and eventually began distributing it as SCO UNIX.

Trusted Xenix was a variant developed by Trusted Information Systems which incorporated the Bell-LaPadula model of multilevel security, and had a multilevel secure interface for the STU-III secure communications device (that is, an STU-III connection would only be made available to applications running at the same privilege level as the key loaded in the STU-III). It was evaluated by formal methods and achieved a B2 security rating under the NSA's Trusted Computer System Evaluation Criteria—the second highest rating ever achieved by an evaluated operating system. Version 2.0 was released in January 1991, version 3.0 in April 1992, and version 4.0 in September 1993. It was still in use at least as of 1995.

EXOKERNEL

An exokernel is a type of kernel that does not abstract hardware into theoretical models. Instead it allocates physical hardware resources, such as processor time, memory pages, and disk blocks, to different programs. A program running on an exokernel can link to a library operating system that uses the exokernel to simulate the abstractions of a well-known OS, or it can develop application-specific abstractions for better performance

NANO KERNEL

A nanokernel delegates virtually all services — including even the most basic ones like interrupt controllers or the timer — to device drivers to make the kernel memory requirement even smaller than a traditional microkernel

HYBRID KERNEL

Hybrid kernels are essentially a compromise between the monolithic kernel approach and the microkernel system. This implies running some services (such as the network stack or the filesystem) in kernel space to reduce the performance overhead[citation needed] of a traditional microkernel, but still running kernel code (such as device drivers) as servers in user space

MICRO KERNEL

The microkernel approach consists of defining a simple abstraction over the hardware, with a set of primitives or system calls to implement minimal OS services such as memory management, multitasking, and inter-process communication. Other services, including those normally provided by the kernel such as networking, are implemented in user-space programs, referred to as servers. Microkernels are easier to maintain than monolithic kernels, but the large number of system calls and context switches might slow down the system because they typically generate more overhead than plain function calls.

A microkernel allows the implementation of the remaining part of the operating system as a normal application program written in a high-level language, and the use of different operating systems on top of the same unchanged kernel. It is also possible to dynamically switch among operating systems and to have more than one active simultaneously

MONOLITHIC KERNEL

In a monolithic kernel, all OS services run along with the main kernel thread, thus also residing in the same memory area. This approach provides rich and powerful hardware access. Some developers, such as UNIX developer Ken Thompson, maintain that monolithic systems are easier to design and implement than other solutions.[citation needed] The main disadvantages of monolithic kernels are the dependencies between system components - a bug in a device driver might crash the entire system - and the fact that large kernels can become very difficult to maintain.

KERNEL

In computer science, the kernel is the central component of most computer operating systems (OS). Its responsibilities include managing the system's resources (the communication between hardware and software components).[1] As a basic component of an operating system, a kernel provides the lowest-level abstraction layer for the resources (especially memory, processors and I/O devices) that application software must control to perform its function. It typically makes these facilities available to application processes through inter-process communication mechanisms and system calls.

These tasks are done differently by different kernels, depending on their design and implementation. While monolithic kernels will try to achieve these goals by executing all the code in the same address space to increase the performance of the system, microkernels run most of their services in user space, aiming to improve maintainability and modularity of the codebase.[2] A range of possibilities exists between these two extremes.

OS/2 operaing system

OS/2 is a computer operating system, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for "Operating System/2," because it was introduced as part of the same generation change release as IBM's "Personal System/2 (PS/2)" line of second-generation Personal Computers. OS/2 is no longer marketed by IBM, and IBM standard support for OS/2 was discontinued on December 31, 2006.[1] Currently, Serenity Systems sells OS/2 under the brand name eComStation.

OS/2 was intended as a protected mode successor of PC-DOS and Microsoft Windows. Notably, basic system calls were modeled after MS-DOS calls; their names even started with "Dos" and it was possible to create "Family Mode" applications: text mode applications that could work on both systems.[2] Because of this heritage, OS/2 is like Windows in many ways, but it also shares similarities with Unix and Xenix.

OS/2 is also remembered for being the first major operating system to have its own advocacy group.[citation needed] Team OS/2 was a grassroots, ad-hoc organization of volunteers, who promoted and supported the operating system and applications designed for it.

IMPORTANT TIPS FOR THOSE WHO ARE USING WINDOWSXP(2)

1. It boasts how long it can stay up. Whereas previous versions of Windows were coy about how long they went between boots, XP is positively proud of its stamina. Go to the Command Prompt in the Accessories menu from the All Programs start button option, and then type 'systeminfo'. The computer will produce a lot of useful info, including the uptime. If you want to keep these, type 'systeminfo > info.txt'. This creates a file called info.txt you can look at later with Notepad. (Professional Edition only).

2. You can delete files immediately, without having them move to the Recycle Bin first. Go to the Start menu, select Run... and type 'gpedit.msc'; then select User Configuration, Administrative Templates, Windows Components, Windows Explorer and find the Do not move deleted files to the Recycle Bin setting. Set it. Poking around in gpedit will reveal a great many interface and system options, but take care -- some may stop your computer behaving as you wish. (Professional Edition only).

3. You can lock your XP workstation with two clicks of the mouse. Create a new shortcut on your desktop using a right mouse click, and enter 'rundll32.exe user32.dll,LockWorkStation' in the location field. Give the shortcut a name you like. That's it -- just double click on it and your computer will be locked. And if that's not easy enough, Windows key + L will do the same.

4. XP hides some system software you might want to remove, such as Windows Messenger, but you can tickle it and make it disgorge everything. Using Notepad or Edit, edit the text file /windows/inf/sysoc.inf, search for the word 'hide' and remove it. You can then go to the Add or Remove Programs in the Control Panel, select Add/Remove Windows Components and there will be your prey, exposed and vulnerable.

5. For those skilled in the art of DOS batch files, XP has a number of interesting new commands. These include 'eventcreate' and 'eventtriggers' for creating and watching system events, 'typeperf' for monitoring performance of various subsystems, and 'schtasks' for handling scheduled tasks. As usual, typing the command name followed by /? will give a list of options -- they're all far too baroque to go into here.

6. XP has IP version 6 support -- the next generation of IP. Unfortunately this is more than your ISP has, so you can only experiment with this on your LAN. Type 'ipv6 install' into Run... (it's OK, it won't ruin your existing network setup) and then 'ipv6 /?' at the command line to find out more. If you don't know what IPv6 is, don't worry and don't bother.

7. You can at last get rid of tasks on the computer from the command line by using 'taskkill /pid' and the task number, or just 'tskill' and the process number. Find that out by typing 'tasklist', which will also tell you a lot about what's going on in your system.

8. XP will treat Zip files like folders, which is nice if you've got a fast machine. On slower machines, you can make XP leave zip files well alone by typing 'regsvr32 /u zipfldr.dll' at the command line. If you change your mind later, you can put things back as they were by typing 'regsvr32 zipfldr.dll'.

9. XP has ClearType -- Microsoft's anti-aliasing font display technology -- but doesn't have it enabled by default. It's well worth trying, especially if you were there for DOS and all those years of staring at a screen have given you the eyes of an astigmatic bat. To enable ClearType, right click on the desktop, select Properties, Appearance, Effects, select ClearType from the second drop-down menu and enable the selection. Expect best results on laptop displays. If you want to use ClearType on the Welcome login screen as well, set the registry entry HKEY_USERS/.DEFAULT/Control Panel/Desktop/FontSmoothingType to 2.

10. You can use Remote Assistance to help a friend who's using network address translation (NAT) on a home network, but not automatically. Get your pal to email you a Remote Assistance invitation and edit the file. Under the RCTICKET attribute will be a NAT IP address, like 192.168.1.10. Replace this with your chum's real IP address -- they can find this out by going to www.whatismyip.com -- and get them to make sure that they've got port 3389 open on their firewall and forwarded to the errant computer.

GNU HURD

GNU Hurd (usually referred to as the Hurd) is a free software computer operating system kernel, released under the GNU General Public License. It has been under development since 1990 by the GNU Project of the Free Software Foundation. It consists of a set of servers (or daemons, in Unix terminology) that work on top of a microkernel; together they form the kernel of GNU. The Hurd aims to surpass Unix kernels in functionality, security, and stability, while remaining largely compatible with them.

HURD is a mutually recursive acronym, standing for HIRD of Unix-Replacing Daemons, where HIRD stands for HURD of Interfaces Representing Depth. It is also a play on the words herd of gnus, reflecting how it works.

I-PHONE OS

iPhone OS is the operating system developed by Apple Inc for the iPhone and iPod touch.[1][2] It is derived from Mac OS X, and is based on the same Mach kernel and Darwin core as Mac OS X. iPhone OS has three abstraction layers: a Core Services layer, a Media layer, and a Cocoa Touch layer. The operating system takes less than half a gigabyte (GB) of the devices' total 4–32 GB storage.[3]

Many of the function of the iPhone and iPod touch are managed through iTunes version 7.3 or later, which runs on Mac OS X version 10.4.10 or later and on 32-bit versions of Windows XP or Vista.[4] The release of iTunes 7.6 expanded this support to include 64-bit versions of Vista.[5]

NEXTSTEP

NEXTSTEP was the original object-oriented, multitasking operating system that NeXT Computer developed to run on its proprietary NeXT computers ("black boxes") such as the NeXTcube. NEXTSTEP 1.0 was released on September 18, 1989 after several previews starting in 1986. The last version, 3.3, was released in early 1995, by which time it ran not only on Motorola 68000 family processors, but also IBM PC compatible x86, Sun SPARC, and HP PA-RISC. Apple Inc.'s Mac OS X is a direct descendant of NEXTSTEP.

NEXTSTEP was a combination of several parts:

a Unix operating system based on the Mach kernel, plus source code from BSD Unix
Display PostScript and a windowing engine
the Objective-C language and runtime
an object-oriented (OO) application layer, including several "kits"
development tools for the OO layers
The key to NEXTSTEP's fame were the last three items. The toolkits offered incredible power, and were used to build all of the software on the machine. Distinctive features of the Objective-C language made the writing of applications with NEXTSTEP far easier than on many competing systems, and the system was often pointed to as a paragon of computer development, even a decade later.

NEXTSTEP's user interface was refined and consistent, and introduced the idea of the Dock, carried through OpenStep and into Mac OS X, and the Shelf. NEXTSTEP also created or was among the very first to sport a large number of other GUI concepts now common in other operating systems: 3D "chiseled" widgets, system-wide drag and drop of a wide range of objects beyond file icons, system-wide piped services, real-time scrolling and window dragging, properties dialog boxes ("inspectors"), window modification notices (such as the saved status of a file), etc. The system was among the first general-purpose user interfaces to handle publishing color standards, transparency, sophisticated sound and music processing (through a Motorola 56000 DSP), advanced graphics primitives, internationalization, and modern typography in a consistent manner across all applications.

Additional kits were added to the product line to make the system more attractive. This included Portable Distributed Objects (PDO), which allowed easy remote invocation, and Enterprise Objects Framework, a powerful object-relational database system. These kits made the system particularly interesting to custom application programmers, and NEXTSTEP had a long history in the financial programming community.

UNICOS

Unicos (officially all-caps UNICOS) is the name of a range of Unix operating system variants developed by Cray for its supercomputers. Unicos is the successor of the Cray Operating System (COS). It provides network clustering and source code compatibility layers for some other Unixes. Unicos was originally introduced in 1985 with the Cray-2 system and later ported to other Cray models. The original Unicos was based on System V.2, and had numerous BSD features (e.g., networking and file system enhancements) added to it.

CX-OS was the original name given to what is now Unicos. This was a prototype system which ran on a Cray X-MP in 1984 before the Cray-2 port. It was used to demonstrate the feasibility of using Unix on a supercomputer system, prior to the availability of Cray-2 hardware.

The operating system revamp was part of a larger movement inside Cray Research to modernize their corporate software: including rewriting their most important Fortran compiler in a higher-level language (Pascal) with more modern optimizations and vectorizations.

As a migration path for existing COS customers wishing to transition to Unicos, a Guest Operating System capability was introduced into COS. The only guest operating system that was ever supported was Unicos. A COS batch job would be submitted to start up Unicos, which would then run as a subsystem under COS - using a subset of the systems CPUs, memory, and peripheral devices. The Unicos that ran under GOS was exactly the same as when it ran stand-alone - the difference was that the kernel would make certain low-level hardware requests through the COS GOS hook, rather than directly to the hardware.

One of the sites that ran very early versions of Unicos was Bell Labs, where Unix pioneers including Dennis Ritchie ported parts of their Eighth Edition Unix (including stream I/O) to Unicos. They also experimented with a guest facility within Unicos, allowing the stand-alone version of the OS to host itself.

SUN-OS

SunOS is a version of the Unix operating system developed by Sun Microsystems for their workstation and server computer systems. The SunOS name is usually only used to refer to versions 1.0 to 4.1.4 of SunOS. These versions were based on BSD Unix, while SunOS version 5.0 and later are based on UNIX System V Release 4, and are marketed under the brand name Solaris

SunOS 1 and 2 supported the Sun-2 series systems, including Sun-1 systems upgraded with Sun-2 (68010) CPU boards. SunOS 3 supported Sun-2 and Sun-3 (68020) series systems. SunOS 4 supported Sun-2 (until release 4.0.3), Sun-3 (until 4.1.1), Sun386i (4.0, 4.0.1 and 4.0.2 only) and Sun-4 (SPARC) architectures. Although SunOS 4 was intended to be the first release to fully support Sun's new SPARC processor, there was also a SunOS 3.2 release with preliminary support for Sun-4 systems.

SunOS 4.1.2 introduced support for Sun's first sun4m-architecture multiprocessor machines (the SPARCserver 600MP series); since it had only a single lock for the kernel, only one CPU at a time could execute in the kernel.

The last release of SunOS 4 was 4.1.4 (Solaris 1.1.2) in 1994. The sun4, sun4c and sun4m architectures were supported in 4.1.4; sun4d was not supported.

Sun continued to ship SunOS 4.1.3 and 4.1.4 until December 27, 1998; they were supported until September 30, 2003.

FEATURES OF MACOS X-OPERATING SYSTEM

Aqua GUI – A fluid graphical user interface with glass-like elements. Anti-aliasing of widgets, text, graphics and window elements. ColorSync color matching built into the core drawing engine, for print and multimedia professionals. Drop shadows around window and isolated text elements to provide a sense of depth. A Dock holding file/folder shortcuts as well as minimized windows. Full-color, scalable icons up to 512x512 pixels Human interface guidelines followed by almost all applications, giving them consistent user interface and keyboard shortcuts. New interface elements including sheets (document modal dialog boxes attached to specific windows) and drawers. OpenGL composites windows onto the screen to allow hardware-accelerated drawing. This technology (introduced in version 10.2) is called Quartz Extreme. Quartz's internal imaging model correlates well with the Portable Document Format (PDF) imaging model, making it easy to output PDF to multiple devices. PDF viewing is built in. When a widget is added to the dashboard, it appears with a ripple effect.Automator – an application designed to create an automatic workflow for different tasks (introduced in version 10.4). Dashboard – A full-screen group of small applications called desktop widgets that can be called up and dismissed in one keystroke (introduced in version 10.4). Exposé – A feature which includes three functions to help accessibility between windows and desktop. Its functions are to instantly display all open windows as thumbnails for easy navigation to different tasks, display all open windows as thumbnails from the current application, and hide all windows to access the desktop (introduced in version 10.3). Finder – A file browser allowing quick access to all areas of the computer (modified throughout subsequent releases). (The Finder found in Mac OS X Jaguar had been criticized by John Siracusa for violating the concept of spatial interface.) Quick Look allows dynamic previews of files (including videos and multi-page documents) without opening their parent applications (introduced in 10.5). Spotlight search technology allows rapid real-time searches of data files, mail messages, photos, and other information, based on item properties (meta data) and/or content (introduced in version 10.4). FileVault – Optional encryption of the user's files with Advanced Encryption Standard (AES) (128-bit keys introduced in version 10.3, 256-bit keys on version 10.5). Front Row – A media viewer interface accessed by the Apple Remote (introduced in 10.4). Global application services – spell checker, special characters palette, color picker, font chooser and dictionary. Integrated Sync Services – A system which allows applications to access a centralized extensible database for various elements of user data, including calendar and contact items. The operating system manages conflicting edits and data consistency (introduced in version 10.4). Spaces – Desktop organization tool which can create and manage multiple virtual desktops and display them in an Exposé-like interface (introduced in 10.5). Cover Flow – is a three-dimensional graphical user interface included with iTunes, the Finder, and other Apple Inc. products for visually skimming through files and digital media libraries via cover artwork (introduced in 10.5). Time Machine – Automatic backup technology that allows users to view and restore previous versions of files and application data (introduced in 10.5).

Mac OS X (pronounced /mæk əʊ ɛs tɛn/[1] or Mac O-S ten) is a line of graphical operating systems developed, marketed, and sold by Apple Inc., the latest of which is pre-loaded on all currently shipping Macintosh computers. Mac OS X is the successor to the original Mac OS, which had been Apple's primary operating system since 1984.

The first version released was Mac OS X Server 1.0 in 1999, which retained the earlier Mac operating system's "platinum" appearance and even resembled OPENSTEP in places. The desktop-oriented version, Mac OS X v10.0, followed in March 2001 sporting the new Aqua user interface. Since then, five more distinct "end-user" and "server" versions have been released, most recently Mac OS X v10.5 in October 2007. Releases of Mac OS X are named after big cats; for example, Apple calls Mac OS X v10.5 "Leopard".

The server edition, Mac OS X Server, is architecturally very similar to its desktop counterpart but usually runs on Apple's line of Macintosh server hardware. It includes workgroup management and administration software tools that provide simplified access to key network services, including a mail transfer agent, a Samba server, an LDAP server, a domain name server, and others.

Apple also produces customized versions of OS X for use on three of its consumer devices, the Apple TV,[2] the iPhone and the iPod touch. The modified OS only contains what is needed for that particular device (un-needed drivers and components are removed), though certain sources have reported that simple hacks could install features in the Mac OS to the stripped down version

The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.
For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop -- it makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system.

Operating systems can be classified as follows:

multi-user : Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.
multiprocessing : Supports running a program on more than one CPU.
multitasking : Allows more than one program to run concurrently.
multithreading : Allows different parts of a single program to run concurrently.
real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

5 ways to speed up your PC

By following a few simple guidelines, you can maintain your computer and keep it running smoothly. This article discusses how to use the tools available in Windows XP Service Pack 2 (SP2) and Windows Vista to more efficiently maintain your computer and safeguard your privacy when you're online.

Free up disk space

By freeing disk space, you can improve the performance of your computer. The Disk Cleanup tool helps you free up space on your hard disk. The utility identifies files that you can safely delete, and then enables you to choose whether you want to delete some or all of the identified files.
Use Disk Cleanup to:
• Remove temporary Internet files.
• Remove downloaded program files (such as Microsoft ActiveX controls and Java applets).
• Empty the Recycle Bin.
• Remove Windows temporary files.
• Remove optional Windows components that you don't use.
• Remove installed programs that you no longer use.

Speed up access to data

Disk fragmentation slows the overall performance of your system. When files are fragmented, the computer must search the hard disk when the file is opened to piece it back together. The response time can be significantly longer.
Disk Defragmenter is a Windows utility that consolidates fragmented files and folders on your computer's hard disk so that each occupies a single space on the disk. With your files stored neatly end-to-end, without fragmentation, reading and writing to the disk speeds up.
When to run Disk Defragmenter
In addition to running Disk Defragmenter at regular intervals—monthly is optimal—there are other times you should run it too, such as when:

•You add a large number of files.
•Your free disk space totals 15 percent or less.
•You install new programs or a new version of Windows.

Detect and repair disk errors

In addition to running Disk Cleanup and Disk Defragmenter to optimize the performance of your computer, you can check the integrity of the files stored on your hard disk by running the Error Checking utility.
As you use your hard drive, it can develop bad sectors. Bad sectors slow down hard disk performance and sometimes make data writing (such as file saving) difficult, or even impossible. The Error Checking utility scans the hard drive for bad sectors, and scans for file system errors to see whether certain files or folders are misplaced.
If you use your computer daily, you should run this utility once a week to help prevent data loss.

Protect your computer against spyware

Spyware collects personal information without letting you know and without asking for permission. From the Web sites you visit to usernames and passwords, spyware can put you and your confidential information at risk. In addition to privacy concerns, spyware can hamper your computer's performance. To combat spyware, you might want to consider using Microsoft Windows Defender, which is included in Windows Vista, and is available as a free download for Microsoft XP SP2. Alternatively, there are other free anti-spyware software programs available.

Learn all about ReadyBoost

If you're using Windows Vista, you can use ReadyBoost to speed up your system. A new concept in adding memory to a system, it allows you to use non-volatile flash memory—like a USB flash drive or a memory card—to improve performance without having to add additional memory.

cp/m operating system

CP/M is an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. Initially confined to single tasking on 8-bit processors and no more than 64 kilobytes (64 KiB) of memory, later versions of CP/M added multi-user variations, and were migrated to 16-bit processors.

The combination of CP/M and S-100 bus computers patterned on the MITS Altair was an early "industry standard" for microcomputers, and was widely used through the late 1970s and into the mid-'80s. By greatly reducing the amount of programming required to install an application on a new manufacturer's computer, CP/M increased the market size for both hardware and software.