Computer Organization Chapter 2

9 Questions

What is the purpose of a context switch in a CPU?

Changing the contents of the central processor's registers with the context information of the new process to be executed.

Which of the following is not a condition for the arrival of an interruption?

The interrupt is disabled.

Simultaneous interruption requests are always processed in a fixed priority order.

False

During an interruption, the central processor suspends the execution of the current program and triggers the execution of a predefined program specific to the event called an ____________ routine.

interrupt

What are the three components of a Von Neumann machine?

Central Memory (CM), Processor or Central Processing Unit (CPU), Peripheral Input/Output Units (I/O)

Which registers are included in the central processor unit (CPU)?

Registers (Data, Addresses, Control, Instruction)

The Program Counter (PC), also known as Instruction Pointer (IP), contains the address of the ______ instruction to be executed.

A process consists of executable code of the running program and a context.

True

Match the parts of a process's memory image:

Code (Text) = Program's instruction code to be executed, read-only access Data = Contains constants and variables Stack = Stores register values, local variables, function parameters, return addresses Heap = Zone for dynamically allocating space during runtime

Study Notes

Von Neumann Machine

A Von Neumann machine is an electronic computer based on memory, comprising Central Memory (CM), Processor or Central Processing Unit (CPU), and Peripheral Input/Output Units (I/O).
The processor executes instructions or actions of a program, making it the brain of the computer.

Central Processor Registers

Registers are a type of internal memory within the CPU, allowing for fast access and temporary storage of results or control information.
The central processor has 5 physical registers: Program Counter (PC), Instruction Register (IR), General Registers (ALU), Stack Pointer (SP), and Program Status Word (PSW).

Processor Execution Cycle

A program is composed of a sequence of instructions, and its execution progresses the state of the machine from one state to another.
The execution cycle consists of: instruction fetch phase, execution phase, and observable point.

Processor Status

The processor status is described by the content of its status register or status word (PSW).
The PSW contains information on the address of the next instruction to execute, current values of condition codes, mode of execution, and interrupt masks.

Program Flow in a System

The transition of a program from its external form to its internal form occurs in several steps: text editing, compilation, linking, and loading.
Each step involves the use of specific software tools, such as a text editor, compiler, linker, and loader.

Concepts of Process and Multiprogramming

A process is a program currently running, with its own characteristics, resources, and state.
A process consists of executable code, context, and memory image (code, data, stack, and heap).
Process Control Block (PCB) represents a process in the OS, containing information on process identity, state, context, CPU scheduling, memory management, I/O state, and accounting information.

Interrupt Systems

An interruption is a response to an event that interrupts the execution of the current program at an observable point.
Interrupt management mechanisms involve wired logic hardware and context switching.
Conditions for the arrival of an interruption include: active interrupt system, observable point, enabled interrupt, and unmasked interrupt.

Types of Interruptions

External or hardware interruptions: caused by components external to the central processor (e.g., time clocks, I/O devices).
Internal or software interruptions: caused by the execution of the program within the PC (e.g., supervisor calls, traps, or exceptions).