Describe about address space and memory space, Computer Engineering

Assignment Help:

Q. Describe about Address Space and Memory Space?

An address used by a programmer will be termed as a virtual address and set of such addresses the address space. An address in main memory is known as a physical address. The set of these locations is termed as memory space. So address space is set of addresses produced by programs as they reference instructions and data, memory space comprises actual main memory locations directly addressable for processing.

Supposes a computer which has a main-memory capacity of 64K words (K=1024). 16-bits are required to specify a physical address in memory because 64K = 216. Assume that computer has auxiliary memory for storing information equivalent to capacity of 16 main memories. Let's signify address space by N and memory space by M we then have for this illustration: N = 16 × 64 K = 1024K and M = 64K.

In a multiprogramming computer system, data and programs are transferred to and from auxiliary memory and main memory based on demands obliged by CPU. Suppose program 1 is currently being executed in CPU. Program 1 and a part of its associated data are moved from secondary memory in the main memory as displayed in Figure below. Parts of programs and data require not being in contiguous locations in memory because information is being moved in and out and empty spaces may be available in scattered locations in memory.

1319_Describe about Address Space and Memory Space.png

Figure: Address and Memory Space in Virtual Memory

In our illustration address field of an instruction code will comprise 20 bits however physical memory addresses should be specified with just 16-bits. So CPU will reference data and instructions with a 20 bits address though information at this address should be taken from physical memory since access to auxiliary storage for particular words will be prohibitively long. A mapping table is then required as displayed in Figure below to map a virtual address of 20 bits to a physical address of 16 bits. Mapping is a dynamic operation that means every address is translated instantly as a word is referenced by CPU.  

323_Describe about Address Space and Memory Space1.png

Figure: Memory table for mapping a virtual table


Related Discussions:- Describe about address space and memory space

Pvm communication model, Q. PVM communication model? A nonblocking rece...

Q. PVM communication model? A nonblocking receive as soon as returns with either data or a flag that data hasn't arrived while a blocking receive returns only when data is in r

Explain the client-server interaction using messages, Explain the Client-Se...

Explain the Client-Server Interaction Using Messages As we have learned, client- server interaction may be managed in many ways. A message- based interaction is perhaps the bes

Manipulate the presentation and attributes interactive list, How can you m...

How can you manipulate the presentation and attributes of interactive lists? ---Scrolling by Interactive Lists. ---Setting the Cursor from within the Program. ---Changing

What is socket inheritance, What is socket inheritance? Explain. Socke...

What is socket inheritance? Explain. Socket Inheritance: In a socket inheritance a reference count mechanism is utilized. Whenever a socket is first created, the system set

What is drop-down list, A dialog box such as a File menu that have one comm...

A dialog box such as a File menu that have one command until it is clicked when a number of dissimilar commands "drop-down."

Convert the following into sop form, Convert the following into SOP form ...

Convert the following into SOP form 1. (A+B) (B'+C) (A'+ C) 2. (A'+C) (A'+B'+C') (A+B') 3. (A+C) (AB'+AC) (A'C'+B)

Ending transactions - data phase, Ending transactions: Either side may...

Ending transactions: Either side may request that a burst end after the present data phase. Simple PCI component that do not support multi-word bursts will always request this

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd