keywords:
Bookmark and Share



Front Back
A single-user system supports multiprogramming.
False
All computers have only a finite amount of memory and if a program doesn’t fit, then either the size of the main memory must be increased or the program must be modified.
True
The first step in loading a job in a single-user system is storing the first memory location of program into the base register (for memory protection).
True
The fixed partition scheme does not require that the entire program be stored contiguously and in memory from the beginning to the end of its execution.
False
To overlay is to transfer segments of a program from main memory into secondary storage for execution, so that two or more segments take turns occupying the same memory locations.
True
Early memory management schemes are still used in today’s operating systems.
True
The algorithm used to store jobs into memory requires a few more steps than the one used for a single-user system because the size of the job must be matched with the size of the partition to make sure it fits completely.
True
The first attempt to allow for multiprogramming used fixed partitions.
True
The fixed partition scheme works well if all of the jobs run on the system are of the same size or if the sizes are known ahead of time and don’t vary between reconfigurations.
True
The problem of partition intrusion is present in single-user contiguous allocation schemes.
False
In a single-user system, jobs are processed ____.
Sequentially
The ____ keeps the free/busy lists organized by memory locations, low-order memory to high-order memory.
First-fit memory allocation
In the algorithm to load a job in a single-user system, the program counter is initially set to ____.
The address of the last memory location
____ has the least wasted space and the smallest partition fitting the requirements.
Best-fit memory allocation
____ is the first step in the algorithm to load a job in a fixed partition.
Determining the job’s requested memory size
Fixed partitions are also called ____ partitions.
Static
In the partition scheme, the table that the Memory Manager uses to keep track of jobs is composed of the ____.
Partition size, memory address, access, and status
The fixed partition scheme works well ____.
When jobs have the same size
Which of the following describes the first memory allocation scheme?
External Fragmentation
____ consists of fragments of free memory between blocks of allocated memory.
7600
Assume the Memory Manager receives a request for a block of 200. When the best-fit algorithm is used, ____ is the beginning address of the block granted by the Memory Manager. Beginning Address        Memory Block Size 4075                        105 5225                        5 6785                        600 7560                        20 7600                        205 10250                       4050 15125                       230 24500                       1000
J3
Consider the following space requirements for jobs 1-4 and memory blocks. Assuming a first-fit scheme is used, the job,____, is not able to run.   Jobs:                 Blocks: J1 10K                B1 30K J2 20K                B2 15K J3 30K                B3 50K J4 10K                B4 20K
J2
Consider the following space requirements for jobs 1-4 and memory blocks. Assuming a best-fit scheme is used, the job,____, is placed in the last block.   Jobs:                 Blocks: J1 10K                B1 30K J2 20K                B2 15K J3 30K                B3 50K J4 10K                B4 20K
Best-fit Memory Allocation
The following algorithm can be described as ____.   Initialize Memory Block(0) = 99999 Compute Initial Memory Waste = Memory Block(0) – Job Size Initialize Subscript = 0 Set Counter to 1 Do While Counter <= Number of Blocks in Memory If Job Size > Memory Size(Counter) Counter = Counter + 1 Else Memory Waste = Memory Size(Counter) – Job Size End If If Initial Memory Waste > Memory Waste Subscript = Counter Initial Memory Waste = Memory Waste Counter = Counter + 1 End If End Do If Subscript = 0 Put Job in Waiting Queue Else Load Job Into Memory Size(Subscript) Adjust Free/Busy Memory Lists End If Go Fetch Next Job
Best-fit Memory Allocation
The following algorithm can be described as ____.   Set Counter to 1 Do While Counter <= Number of Blocks in Memory If Job Size > Memory Size(Counter) Counter = Counter + 1 Else Load Job Into Memory Size(Counter) Adjust Free/Busy Memory Lists Go Fetch Next Job End If End Do Put Job in Waiting Queue Go Fetch Next Job
First-fit Memory Allocation
x of y cards