IO Inputoutput IPC Inter process communication A mechanism by which unix

Io inputoutput ipc inter process communication a

This preview shows page 94 - 96 out of 102 pages.

I/O : Input/output. IPC : Inter-process communication. A mechanism by which unix processes can exchange data with one another. See also RPC. kernel : The core of a multitasking operating system which deals with the basic system resources. The kernel drives physical devices and handles I/O, memory management and process scheduling. Loopback : The loopback device is a pseudo network device in the UNIX operating system which, rather than sending data out onto a physical network, sends packets straight back into the system. The protocols for talking to the loopback device are the same as those for the physical network, so programs employing interprocess communication have only to hold to a single standard, regardless of whether the processes are on the same machine, or on different machines. Machine code : The basic numerical language of codes which the CPU understands. Compilers and assemblers convert programs into machine code. Multiplex : To switch between several activities or devices. Multi-user system : An operating system where several users can use the system simultaneously. OS : Operating system. Parallel : Parallel processes are not merely timeshared (concurrent) but actually run simultaneously on different CPUs. Pixel : A single dot on the screen. This is one `grain' - or the object of maximum resolution. Primary memory : RAM internal memory (see secondary memory). Primitive : A very low level function or routine. A basic element in a library of functions. RISC : Reduced instruction set chip. This is part of a new philosophy to make microprocessors faster by giving them fewer (less complicated) instructions which are optimized to run very fast. Usually each instruction completes in a single clock cycle. RPC : Remote Procedure Call. This is a mechanism for executing tasks on remote machines across the network. The RPC protocol makes use of the XDR (external data representation) protocol for passing data. It is a relatively high level interface between networked machines. Secondary memory : Disk or tape storage. Semantics : This term is used to describe the `method of operation' of a particular system. The prescribed way in which a particular system is supposed to behave. The logic of operation of the system. Single-user system : A system in which only one user can use the system at a time. Starvation : A process is said to starve if it never gets a share of the CPU. This can occur is there are errors or deadlocks in scheduling. Transparently : This word is often used to mean that something happens without anyone needing to know the details about how it happens. For example, the OS
Image of page 94
handles timesharing transparently - i.e. without users needing to know about how it happens. Vector : An array of data or a segment of memory.
Image of page 95
Image of page 96

You've reached the end of your free preview.

Want to read all 102 pages?

  • One '20

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask ( soon) You can ask (will expire )
Answers in as fast as 15 minutes
A+ icon
Ask Expert Tutors