COM581 Class Test #1 Week #1 Notes - created from Mind Map

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I/O

Input: Obtains raw data from the user.

Process: Handled by processor - turns data into information.

Output: Displays information.

Storage: Storing of the data/information.

CPU - Consists of:

Preforms the fetch-execute cycle.

Memory

Operating System - (Kernel)

- An OS provides mediate access to CPU, Memory & I/O Devices. It manages hardware and software.

OS Handles tasks such as:

- Process Management.

- Memory Management.

- I/O.

- Device Drivers.

- UI.

Segmented into following layers: 1. User at the top.

2. Hardware at the bottom.

3. App software and OS components at intermediate layers.

Linux Architecture

1 . User Applications.

2. GNU C Library.

3. System Call Interface.

4. Kernel.

5. Architecture-Dependent Kernel Code.

(Refer to week 1 lecture notes pg. 64 for visual representation).

Virtual Machines

- A VM emulates a computer system.

- Host OS = The OS & hardware running the actual machine and VM.

- Guest OS = The OS in controlled via the Virtual Machine Manager (VMM) which is running on the host OS.

VM Advantages:

1. Multi-Platform Expandable.

2. Cost saving and scalable.

3. Security.

4. Fewer physical resources required.

5. Remote access.

6. Gain administrative experience.

VM Disadvantages:

1. Virtual servers are expensive, however client software is often free.

2. VM software is processor and memory intensive.

3. Storage: Multiple VMs can used TB's worth of storage.

Control Unit:

- Handles the fetch-execute cycle.

- Controls other components of computer through signals.

- Contains registers (storage locations) for important information.

Arithmetic Logic Unit (ALU):

- Digital circuits to perform arithmetic and logic operations.

- Data registers to store data used by current set of instructions.

Volatile/Non-Volatile Memory

- Volatile = Memory/Contents lost when power is lost.

- Non Volatile = ROM memory that is limited in usages.

Memory Hierarchy

- The faster the memory the higher its located in the hierarchy. (Include Registers, Cache, Main Memory SRAM/DRAM).

- Storage memory is held in the lower portions of the memory hierarchy (For example - Hard Disk).

RAM/Cache/Disk

All volatile memory (temp).

Main Functions of Kernel:

- Process Management: Determines which processes are allowed to use the CPU.

- Memory Management:

Keep track of memory - I.E what memory is allocated to each process and what memory is free (available).

- Device Drivers:

The interface between the hardware and processes.

- I/O: Manages input and output devices.