Distinguish between three types of scheduler?
Operating systems may feature up to 3 distinct types of schedulers: a long-term scheduler (also known as an admission scheduler or high-level scheduler), a mid-term or medium-term scheduler and a short-term scheduler . The names suggest the relative frequency with which these functions are performed.
The long-term, or admission, scheduler decides which jobs or processes are to be admitted to the ready queue; that is, when an attempt is made to execute a program, its admission to the set of currently executing processes is either authorized or delayed by the long-term scheduler. Thus, this scheduler dictates what processes are to run on a system, and the degree of concurrency to be supported at any one time - ie: whether a high or low amount of processes are to be executed concurrently, and how the split between IO intensive and CPU intensive processes is to be handled. In modern OS's, this is used to make sure that real time processes get enough CPU time to finish their tasks. Without proper real time scheduling, modern GUI interfaces would seem sluggish.
Long-term scheduling is also important in large-scale systems such as batch processing systems, computer clusters, supercomputers and render farms. In these cases, special purpose job scheduler software is typically used to assist these functions, in addition to any underlying admission scheduling support in the operating system.
The mid-term scheduler temporarily removes processes from main memory and places them on secondary memory (such as a disk drive) or vice versa. This is commonly referred to as "swapping out" or "swapping in" (also incorrectly as "paging out" or "paging in"). The mid-term scheduler may decide to swap out a process which has not been active for some time, or a process which has a low priority, or a process which is page faulting frequently, or a process which is taking up a large amount of memory in order to free up main memory for other processes, swapping the process back in later when more memory is available, or when the process has been unblocked and is no longer waiting for a resource.
In many systems today (those that support mapping virtual address space to secondary storage other than the swap file), the mid-term scheduler may actually perform the role of the long-term scheduler, by treating binaries as "swapped out processes" upon their execution. In this way, when a segment of the binary is required it can be swapped in on demand, or "lazy loaded".
The short-term scheduler (also known as the CPU scheduler) decides which of the ready, in-memory processes are to be executed (allocated a CPU) next following a clock interrupt, an IO interrupt, an operating system call or another form of signal. Thus the short-term scheduler makes scheduling decisions much more frequently than the long-term or mid-term schedulers - a scheduling decision will at a minimum have to be made after every time slice, and these are very short.
This scheduler can be preemptive, implying that it is capable of forcibly removing processes from a CPU when it decides to allocate that CPU to another process, or non-preemptive (also known as "voluntary" or "co-operative"), in which case the scheduler is unable to "force" processes off the CPU.
The features that distinguish the three types of muscular tissue are structure, location, function, and means of activation. Structure can include straiated, smooth or rough. Location is where in the body . Function can include beating the heart, lifting an object. Finally means of activation could be voluntary or involuntary.
DISPATCHER? The dispatcher is the module that gives control of the CPU to the process selected by the short-time scheduler(selects from among the processes that are ready to execute). The function involves : Swithching context Switching to user mode Jumping to the proper location in the user program to restart that program. SCHEDULER? Normally there are 3 types of schedulers are available in operating systems. 1. Long term scheduler 2. Mid term scheduler 3. Short…
The classification of lines of evidence into five different types is quite arbitrary. One could as easily distinguish two types, or five, or ten, depending on the criteria used. The difference between them would depend on the criteria chosen. For instance: one might distinguish between evidence stemming from research in extant lifeforms on one hand, and from extinct lifeforms on the other. One might distinguish between genetic data and morphological data. For information on various…
Distinguish between abiotic and biotic factors. Biotic Factors: relates to the biological parts of the environment features include: · All the living organisms · How many types there are · Their numbers · Distribution and · Interactions Abiotic Factors relates to the physical parts of the environment this includes chemical factors like · Temperature · Rainfall · Type of soil · Salinity of water
Skeletal muscle, voluntary/striated muscle, is connected to the bone by tendons and is responsible for movement and posture. Smooth muscle, involuntary/non-striated muscle, is found in most structures and organs except the heart. The muscle found specifically in the heart is called cardiac muscle or myocardium.
The aromatic compounds have higher ratio of carbon as compare to corresponding aliphatic compounds so aromatic compounds burn with soot (dark black smoke) due to unburned particles of carbon while aliphatic compounds burn without soot (Exceptions are there) so this is a simple test to distinguish between two types of compounds.
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Primitive types are the data types provided by a programming language as basic building blocks. Primitive types are also known as built-in types or basic types. Depending on the language and its implementation, primitive types may or may not have a one-to-one correspondence with objects in the computer's memory. However, one usually expects operations on primitive types to be the fastest language constructs there are. Integer addition, for example, can be performed as a single…
This word means to be able to tell several similar-looking things apart. While all seeds look the same to me, a bird has special vision that helps it to distinguish between different types. (There is also an adjective, "distinguished," which means very respected, coming from an excellent background or social class: The president of our university comes from a distinguished family of scholars.)