Notes, summaries, assignments, exams, and problems for Computers

Intranet:=Internet is private network which operated by large company which use internet topologies and it is globle.

Extranet:=Extranet is an intranet that is accessible to some people from outside the company.

Internet:=It is a worldwide system of computer network.

Intranet exteanet:

An intranet is a private network, operated by a large company or other organisation, which uses internet technologies, but is insulated from the global internet. An extranet is an intranet that is accessible to some people from outside the company, or possibly shared by more than one organisation

The major difference from an extranet, however, is that an intranet is used internally. While an extranet allows businesses to communicate with clients and vendors,... Continue reading "j" »

Framing bit stuffing:

Framing in Computer Network. Data link layer is responsible for something called Bit Stuffing in Computer Network. It is the division of stream of bits from network layer into manageable units (called frames). Frames could be of fixed size or variable size. Bit stuffing is the insertion of non-information bits into data.

framing: A frame is a digital data transmission unit in computer networking and telecommunication.

Bit Stuffing: Bit stuffing is the process of inserting non-information bits into data to break up bit patterns to affect the transmission of the network.

Byte Stuffing: It is a process that transforms a sequence of data bytes that may contain illegal or reserved values.

Memory Management Problems and Solutions

Deadlock Scenario

A system has four processes and five allocable resources. The current allocation and maximum needs are as follows:

What is the smallest value of x for which this is a safe state?

The needs matrix is as follows:

• 0 1 0 0 1
• 0 2 1 0 0
• 1 0 3 0 0
• 0 0 1 1 1

If x is 0, we have a deadlock immediately. If x is 1, process D can run to completion. When D is finished, the available vector is 1 1 2 2 1. Now, A has ‘10211’ and ‘11221’ is available which together satisfies maximum need. So, A is finished and now ‘2 1 4 3 2’ is available, which can satisfy C. Once C is done, the available resources are 3 2 4 4 2, which can help B finish. So, x =1 will do.

Memory Compaction

A swapping system eliminates... Continue reading "Memory Management: Algorithms and Techniques" »

TEXTO 1 • TELEGRAPH

Telegraph, an electrically operated device or system for distant communication (the first ever invented) by means of visible or audible signals. The method used throughout most of the world, based in large part on the mid-19th-century work of Samuel F.B. Morse, utilizes an electric circuit set up customarily by using a single overhead wire and employing the earth as the other conductor to complete the circuit. In the telegraph's simplest form, an electromagnet in the receiver is activated by alternately making and breaking the circuit. Reception by sound, with the Morse code signals received as audible clicks, is the basis for a low-cost, reliable method of signaling. In addition to wires and cables, telegraph messages... Continue reading "History and Function of Telegraph, Cellular Telephone, and Computer" »

5. A machine has a 32-bit address space and an 8-KB page. The page table is entirely in hardware, with one 32-bit word per entry. When a process starts, the page table is copied to the hardware from memory, at one word every 100 nsec. Lf each process runs for 100 msec (including the time to load the page table), what fraction of the CPU time is devoted to loading the page tables?

The page table contains 232 /213 entries, which is 524,288.  Loading the page table takes 52 msec. If a process gets 100 msec, this consists of 52 msec for loading the page table and 48 msec for running. Thus 52% of the time is spent loading page tables.

6. Suppose that a machine has 48-bit virtual addresses and 32-bit physical addresses. If pages are 4 KB, how many... Continue reading "Understanding Paging and Virtual Memory in Computer Architecture" »

Traffic Server Client Request and Response API Functions

This document describes the Traffic Server API functions related to client requests and responses.

Client Request Functions

Loop Invariant:

Big-Theta, Big-Oh, Big-Omega

The application of several binary codes in microprocessor technique

Nbà + integer arithmetic, table/matrix indexing, event counting., C2à integer arithmetic, exponents in floating point notation.,Bcdà Faults:not effetive use of binary Word, absence of sign., Grayà code disksor bars to control position of moving elements., AScià Communication(text), service of: mosaic display, printers, autonomous keyboards.

Neuman:

It has a single storage system, Processor needs two clocks cycles. Dont use pipeline, Only one bus is used for both data transfers, older

Harvards:

It has two separated memories, 1 cycle if appropiate pipeling strategies, It has separate data and instruction busses, modern

Enumerate the phases of processor instruction execution.

Instruction... Continue reading "Microprocessor Techniques: Binary Codes and Instruction Execution" »

Code in MIPS to add the 4 integer variables: a, b, c, d.

Add e,a,b # a gets b+c or a,b,c # a gets b+c

Add e,e,c # a gets a+dor a,a,c, # a gets a+d

Add e,e,d # a gets a+ eor a,a,e # a gets a+e

Code in MIPS for: f = (g + h) ‐ (i + j);

or #f,.., j are mapped to $s0, ., $s4
add t0,g,h #temp t0=g+hadd $t0,$s1,$s2

add t1,i,j #temp t1=i+jadd $t1,$s3,$s4

sub f,t0,t1 #f=t0-t1sub $s0,$t0,$t1

Why the size of a register is 32 bit?

32 bit occurs frequently and thus in MIPS, it has a special name ‘word’. Size 32 aligns well with the MIPS instruction format.

‘MIPS is Big Endian’ – what does it mean?

Most significant byte at least address of a word.

What are lw and sw instructions used for?

MIPS data transfer instructions with an address to access particular... Continue reading "MIPS Code Examples and Register Optimization" »

Routing in Packet Switching Networks • Key design issue for (packet) switched networks  • Select route across network between end nodes • Characteristics required:

– Correctness – Simplicity – Robustness – Stability  – Fairness  – Optimality – Efficiency

Internet Routing Protocols • Routers are responsible for receiving and forwarding packets through the interconnected set of networks – Makes routing decisions based on knowledge of the topology and traffic/delay conditions of the internet – Routers exchange routing information using a special routing protocol Ø Two concepts in considering the routing function: – Routing information Ø Information about the topology and delays of the internet – Routing algorithm... Continue reading "Which two statements are true about the router ID in a single area OSPF network" »