In a basic segmental storage management system, what constitutes a logical address?

Segment number and within-segment offset.

In a segment-managed system, the logical address is divided into segment numbers and in-page offsets.

The address in this problem has a total of 24 bits, and 8 bits are used to represent the segment number, so the remaining 16 bits are all used to represent the offset within the segment to maximize the length of each segment, so that the maximum allowable length of each segment is 2 16.

The generation is related to the burning of the old modular direct object segment cavity of the program, and the segment management is carried out through the segment table, including the segment number or segment name, the segment starting point, the loading bit, the length of the segment, etc. In addition, the main memory is required.

Occupied region table and main memory availability zone table.

The address has a total of 24 digits, and the segment number occupies 8 digits, so the address in the segment is 24-8=16 (bits), and the maximum length of each segment is 216

Summary. A good pro The combination of these two parts is determined by the page size, for example the page size is 4kb (i.e. 2 bytes to the power of 12), then in the logical address the upper 12 bits are the page number and the lower 12 bits are the offset. In practice, the logical address of the memory may contain other information, such as segment numbers or intra-segment offsets, depending on the specific storage management scheme and the design of the operating system.

Used to represent the offset address in the page, usually occupying the low-level address portion. Hope mine can help you.

You've done a great job! Can you elaborate on that?

A good pro The combination of these two parts is determined by the page size, for example the page size is 4kb (i.e. 2 bytes to the power of 12), then in the logical address the upper 12 bits are the page number and the lower 12 bits are the offset. In practice, the logical address of the memory may contain other information, such as segment numbers or intra-segment offsets, depending on the specific storage management scheme and the design of the operating system.

Summary. What are the parts of the logical address of the memory?

Can you tell us more about that?

The logical address of a memory consists of two parts: a segment address and an offset address. When using segmented storage management, the logical address consists of a segment address and an offset address. When scrambling is managed with paged storage, the logical address consists of a page number and an in-page offset address.

The segment address is used to determine the segment in which it is located, and the offset address or in-page bias and shift address are used to determine the specific address in the segment or page. By converting a logical address into a physical address, the CPU is able to access the specific data in the memory.

Analysis: The storage unit of the main memory is measured in bytes, and the address of the main memory space with a capacity of n is called the absolute address of the main memory, and the main memory space corresponding to the absolute address is called the physical address space. For the convenience of the user, each user can think of the programs and data of their own work as being stored in a set of contiguous spaces starting from "0".

The address used in the user's program is called a logical address. The storage space corresponding to a logical address is called a logical address space.

The address structure of segment and page storage management is very similar, but there are substantial differences between them, which is manifested in the fact that the logical address of the page is continuous, the logical address of the segment can be discontinuous, the address of the page is one-dimensional, the address of the segment is two-dimensional, the paging is carried out by the operating system, the segmentation is determined by the user, and each page can be stored in the main memory in a dispersed manner, and each segment must occupy a continuous main memory space.

Expansion: Each page can be stored in the main memory in a decentralized manner, and each segment must occupy a continuous main storage space. Pagination and segmenters are determined and performed by the operating system. Both page and segment formats use dynamic repositioning.

The address space of the process: It is divided into several segments according to the logical relationship of the program itself, each segment has a segment name (in low-level languages, programmers use segment names to program), and each segment is addressed from 0.

Memory allocation rules: Segments are allocated in units, and each segment occupies a contiguous space in memory, but each segment can not be adjacent to each other.

In page storage management, when the CPU forms a valid address, the page table needs to be checked. This is made possible by hardware.

The main driver for moving from continuous allocation to paging storage management is to improve memory utilization.

Advantages: It retains all the benefits of segmentation and request paging storage management, provides virtual storage space, and makes more efficient use of primary memory.

Disadvantages: increased hardware cost and large system complexity.

The address structure of segment and page storage management is very similar, but there are substantial differences between them, as follows:

A The logical address of a page is sequential, and the logical address of a segment can be discontinuous.

b Addresses in page form are one-dimensional, and segment addresses are two-dimensional.

c Paging is done by the operating system, and segmentation is determined by the user.

The D page type adopts the static repositioning mode, and the segment type adopts the dynamic repositioning mode.

Correct answer: B

Analysis: Each page can be stored in the main memory in a dispersed manner, and each segment must occupy a continuous main memory space, option A is incorrect: the pagination and segmentation are determined and carried out by the operating system, and option c is not correct in the state; Both the page and segment formats are dynamically relocated, and option d is also incorrect.