CASE STUDY #1 - EXAMPLE OF EACH CATEGORY OF AN OPERATING SYSTEM

Batch System OS Example

The IBM System/360 mainframe

BOS/360 (Basic Operating System/360) was an early IBM operating system that was made only for the IBM/360. It came in 2 versions, 4K BOS and 8K BOS.

The operating system disk contained a source language library, a macro library and a core image library. The macro library included all the options for the supervisor, which was assembled by the 360 assembly language compiler, the only language available at the time, although RPG came a little later. The other crucial component was the Job Controller, which was fed by punched cards using JCL (Job Control Language). Most BOS users upgraded to DOS and added more core, typically to 32K or even a gargantuan (for the time) 64K. DOS was the first System/360 operating system to introduce multi-programming. It could be configured with 2 foreground partitions, typically used for spooling while the main JOB Stream ran in the background.

Interactive System OS Example

CDC 6000

KRONOS is an operating system with time-sharing capabilities, written by Control Data Corporation in the 1970s. KRONOS ran on the 60-bit CDC 6000 series mainframe computers and their successors. CDC replaced KRONOS with the NOS operating system in the late 1970s, which were succeeded by the NOS/VE operating system in the mid-1980s.

The MACE operating system and APEX were forerunners to KRONOS. It was written by Control Data systems programmer Greg Mansfield, Dave Cahlander, Tate and 3 others.

Real-Time System OS Example

QNX (pronounced either Q-N-X or Q-nix) is a commercial POSIX-compliant Unix-like real-time operating system, aimed primarily at the embedded systems market. As of September 12 2007, the source of the QNX kernel has been released for non-commercial use.

QNX default desktop

The QNX kernel contains only CPU scheduling, interprocess communication, interrupt redirection and timers. Everything else runs as a user process, including a special process known as proc which performs process creation, and memory management by operating in conjunction with the microkernel. This is made possible by two key mechanisms – subroutine-call type interprocess communication, and a boot loader which can load an image containing not only the kernel but any desired collection of user programs and shared libraries. Message handling is prioritized by thread priority.

Hybrid System OS Example

Screenshot of Windows XP

Windows XP is an operating system that was produced by Microsoft for use on personal computers, including home and business desktops, laptops, and media centers. It was first released in August 2001, and is the most popular version of Windows, based on installed user base. The name "XP" is short for "eXPerience".

Windows XP was eventually released for two additional architectures, Windows XP 64-bit Edition for IA-64 (Itanium) processors and Windows XP Professional x64 Edition forx86-64.            

Embedded System OS Example

Screenshot of Windows XP Embedded Evaluation

 running several Windows components.

Windows XP Embedded, commonly abbreviated "XPe", is a componentized version of the Professional edition of Windows XP. An original equipment manufacturer is free to choose only the components needed thereby reducing operating system footprint and also reducing attack area as compared with XP Professional. Unlike Windows CE, Microsoft's operating system for portable devices and consumer electronics, XP Embedded provides the full Windows API, and support for the full range of applications and device drivers written for Microsoft Windows. The system requirements state that XPe can run on devices with at least 32 MB Compact Flash, 32 MB RAM and a P-200 microprocessor. XPe was released on November 28, 2001. As of October 2008, the newest release is Windows XP Embedded Service Pack 3.

The devices targeted for XPe have included automatic teller machines, arcade games, slot machines, cash registers, industrial robotics, thin clients, set-top boxes, network attached storage(NAS), time clocks, navigation devices, railroad locomotives, etc. Custom versions of the OS can be deployed onto anything but a full-fledged PC; even though XPe supports the same hardware that XP Professional supports (x86 architecture), licensing restrictions prevent it from being deployed on to standard PCs. However, Microsoft has made some exceptions to this rule, allowing XPe alongside a standard OEM install of Windows. Some Dell notebooks contain an embedded XP installation as part of the MediaDirect 2.0 feature, and they were also found on some Acer ones as well as the Samsung Q1.