Lecture 1 Flashcards
What are the 4 basic elements of Operating systems?
Processor
Main memory
System Bus
I/O Modules
What is a computer program?
Instructions to make a computer do something
What is a computer programming/scripting?
Computer programming is the process of writing or editing source code
What is software development?
Writing computer programs.
What is an algorithm?
An ordered set of unambiguous, executable steps that defines a terminating process.
what is a computer?
A computer consists of a CPU, memory, hard disk, monitor, printer, and
communication devices.
What is the system bus?
The System Bus Provides for communication among processors, main
memory, and I/O modules
What are storage devices?
Programs and data are permanently stored on storage devices and are
moved to memory when the computer actually uses them.
Disk drives (hard disks)
– CD/DVD ROM drives (Recordable, Re-Writable, double layer e.t.c.),
– Tape drives.
Differnce between RAM and ROM
Memory (RAM) is volatile, because information is lost when the power is off
Why do we need memory? (rom&ram)
Memory is to store data and program instructions for CPU to execute.
What is a memory unit?
A memory unit is an ordered sequence of bytes, each holds eight bits. A program
and its data must be brought to memory before they can be executed.
A memory byte is never empty, but its initial content may be meaningless.
The current content of a memory byte is lost whenever new information is placed in
it.
What is cache memory?
• Invisible to the OS
• Interacts with other memory management hardware
• Processor must access memory at least once per instruction
cycle
• Processor execution is limited by memory cycle time
• Exploit the principle of locality with a small, fast memory
What does the CPU do?
Central Processing Unit- It retrieves instructions from memory and executes them.
Measured in Megahertz (MHz), with 1 MHz = 1 million pulses per second.
What is a processor?
Controls the operation of the computer
Performs the data processing functions
Referred as CPU
What is a Network Interface Card(NIC) ?
A Network Interface Card (NIC) is a device to connect a computer to a
Local Area Network (LAN). A typical type of NIC, can transfer data through
an Ethernet cable at 10-100 Mbps
What are input devices?
Input devices are devices that a user can interact with a computer by giving instructions to a program or directly to the OS.
Keyboards,
Mouse
What are the three techniques for I/O operations?
Programmed I/O
Interrupt-Driven I/O
Direct Memory Access (DMA)
What is a low-level language (machine language)?
Uses 1s and 0s to create instructions example binary language (100100111)
What is a middle level language (assembly language)?
Uses mnemonics to create instructions Assembly language (ADD A, B)
What is a high level language?
The high-level languages are English-like and easy to learn and program.
JAVA, C, C++
What is machine language? and its cons?
Machine language is a set of primitive instructions built into every
computer.
instructions in binary code
cons?
Tedious process.
Highly difficult to read and modify
What is Assembly language?
developed to make programming easier.
Since the computer cannot understand assembly language, however, a
program called assembler is used to convert assembly language programs
into machine code
What is source code?
A program written in a high-level language is called a source program and includes source code.
What is a compiler?
Since a computer cannot understand a source program, a program called
a compiler is used to translate the source program into a machine
language program called an object program.
What are the two steps in instruction execution?
1) Processor reads (fetches) instructions from memory
2) Processor executes each instruction
