1. Batch Systems
Ø A batch system is one in which jobs are bundled together with the instructions necessary to allow them to be processed without intervention.
ØA batch process is one that runs without user interaction, such as the execution of a script. Often, batch processes are run automatically by some kind of scheduler, or in response to submission into a queue.
Example OS for batch processing:
OS/360
OS/360, officially known as IBM System/360 Operating System, was a batch processing operating system developed by IBM for their then-new System/360 mainframe computer announced in 1964; it was heavily influenced by the earlier IBSYS/IBJOB and Input/Output Control System (IOCS) packages. It was among the earliest operating systems to make direct access storage devices a prerequisite for their operation.
2. Interactive Systems
Ø An operating system that allows users to run interactive programs. All operating systems that are on PCs are interactive OS's.
Ø Requires time-sharing software, which allows each user to interact directly with the computer.
Example OS for batch operating system:
Dartmouth Time Sharing System
The Dartmouth Time-Sharing System, or DTSS for short, was the first large-scale time sharing system to be implemented successfully. Its implementation began at Dartmouth College in 1963 by a student team under the direction of John Kemeny and Thomas Kurtz with the aim of providing easy access to computing facilities for all members of the college. By 1964 the system was in use where it remained so until the end of 1999. DTSS was originally implemented to run on a GE-200 series computer with a GE Datanet 30 as a terminal processor that also managed the 235. Later, DTSS was re-implemented on the GE 635, still using the Datanet 30 for terminal control. The 635 version provided interactive time-sharing to up to nearly 300 simultaneous users in the 1970s, a very large number at the time.
Interactive system would be usable if there is an interaction with the user. Therefore, this kind of operating system will not work out or do the task if command of the user is lacking. 2. Real-time Systems
Ø A real-time operating system (RTOS) is an operating system that is intended to serve real time application requests.
Ø Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems.
Example of Interactive System OS:
RTLinux
RTLinux or RTCore is a hard realtime RTOS microkernel that runs the entire Linux operating system as a fully pre-emtive process.
It was developed by Victor Yodaiken (Yodaiken 1999), Michael Barabanov (Barabanov 1996), Cort Dougan and others at the New Mexico Institute of Mining and Technology and then as a commercial product at FSMLabs. Wind River Systems acquired FSMLabs embedded technology in February 2007 and now makes a version available as Wind River Real-Time Core for Wind River Linux.
RTLinux was based on a lightweight virtual machine where the Linux "guest" was given a virtualized interrupt controller and timer - and all other hardware access was direct. From the point of view of the real-time "host", the Linux kernel is a thread. Interrupts needed for deterministic processing are processed by the real-time core, while other interrupts are forwarded to Linux, which runs at a lower priority than real time threads. Linux drivers handle almost all I/O. First-In-First-Out pipes (FIFOs) or shared memory can be used to share data between the operating system and RTCore.
2. Hybrid Systems
Ø The hybrid operating system approach which is to combine a general-purpose operating system with a real-time operating system is a promising approach to satisfy the real-time property, which is a usually required or embedded system.
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement consumer versions of Windows that were based on MS-DOS. NT was the first fully 32-bit version of Windows, whereas its consumer-oriented counterparts, Windows 3.1x and Windows 9x, were 16-bit/32-bit hybrids. Windows 2000, Windows Xp, Windows Server 2003, Windows Vista, Windows Home Server, Windows Server 2008 and Windows 7are based on Windows NT, although they are not branded as Windows NT.
2. Embedded System
Ø Computers placed inside other products
Ø Designed to perform one or a few dedicated functions often with real time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. Embedded systems control many devices in common use today.
Sample OS for embedded systems:
Windows CE (also known officially as Windows Embedded Compact or Windows Embedded CE post version 6.0 , and sometimes abbreviated WinCE)
-is an operating system developed by Microsoft for minimalistic computers and embedded systems. Windows CE is a distinct operating system and kernel, rather than a trimmed-down version of desktop Windows. It is not to be confused with Windows Xp embedded which is NT-based. Microsoft licenses Windows CE to OEMs and device makers. The OEMs and device makers can modify and create their own user interfaces and experiences, while Windows CE provides the technical foundation to do so. Windows CE is supported on Intel x86 and compatibles,MIPS, ARM and Hitachi SuperH processors.
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