Software & OS Flashcards
What code is directly executable by a processor?
Machine Code
What code is directly convertible to machine code?
Assembly Code
What code has minimal abstraction from the processor?
Low-Level Code
What is high level code?
Complete abstraction of the processor.
What is firmware?
Software embedded in non-volatile memory, such as ROM.
What level of code is firmware typically?
Machine Code
What is an example of software for an information worker?
Excel, Access, Word, email
What kind of application software are games?
Entertainment
What is an example of Educational software?
Rosetta Stone
This type of software is used for experiencing flight
Simulation
Game development tools are an example of what type of application software?
Media Development
What does CAD stand for?
Computer-Aided Development
What is an example of product engineering software?
AutoCAD
What does IDE stand for?
Integrated Development Environment
What are some examples of Programming Tools?
Compilers, debuggers, interpreters, linkers
What is a program or piece of software that is so necessary or desirable that it proves to be the core of some larger technology?
Killer App
What was the first Killer App?
VisiCalc
What program is needed to convert Assembly Code to Machine Code?
Assembler
What are the 3 main OS duties?
1) Hardware interface
2) File management
3) Multitasking
What program became the kernel?
The Monitor
Which program is always running on the computer?
The Kernel
What does the kernel do?
Connects the application software to the hardware of a computer.
What is the first program to run when a computer is turned on?
Bootstrap program
What signals an event?
Interrupt
What are the two most common USES of interrupts?
1) I/O
2) Time-sharing/ countdown timer
What are the two TYPES of interrupts?
1) Polling
2) Vectored
What type of interrupt requires the OS to figure out which I/O device is ready to be read?
Polling
What does an interrupt transfer control to?
The Kernel
What is an Interrupt Vector
A table of pointers holding addresses for interrupt service routines
How does the OS preserve the state of the CPU during an interrupt?
In the registers.
What kind of interrupt is triggered by a currently executing instruction?
A Trap
Dividing by zero is an example of:
A Trap Interrupt
Time-Sharing is the evolution of:
Multiprogramming
The OS keeping several programs in memory and switching execution between them is called:
Multiprogramming
What are the 2 modes of operation with the OS?
1) User Mode
2) Kernel Mode
What are 3 other ways to say kernel mode?
1) Supervisor Mode
2) System Mode
3) Privileged Mode
How is the current OS mode (user, kernel) indicated?
A bit called the mode. User mode = 1, Kernel mode = 0
What mode does the computer start in?
Kernel mode
When a system call occurs, what happens to the OS mode?
Switches from user to kernel
In what mode are privileged instructions executed?
Kernel mode
What kind of instruction is I/O control?
Privileged
What kind of instruction is Timer Management?
Privileged
What kind of instruction is Interrupt Management?
Privileged
What kind of instruction is Reading Processor Status?
Non-privileged
What kind of instruction is Reading System Time?
Non-privileged
What kind of instruction is Context Switching?
Privileged
What kind of instruction is Generating a Trap?
Non-privileged
What kind of instruction is Sending a Final Printout?
Non-privileged
What are the 8 services provided by the OS?
1) Program Execution
2) I/O Operations
3) File System
4) Communications
5) Resource Allocation
6) Accounting
7) Error detection
8) Security
What is a system call?
Provides API to services by the OS
What are the 6 categories of system calls?
1) Process Control
2) File Management
3) Device Management
4) Information Maintenance
5) Communications
6) Protection
What is a process?
Any instance of a program in execution.
What specifies the next instruction to execute in a process?
Program Counter
Text Section (MEMORY)
The executable code
Data Section (MEMORY)
Global variables
Heap Section (MEMORY)
Memory that is dynamically allocated during program runtime
Stack Section (MEMORY)
Local Variables and temporary storage when invoking functions.
What is the highest level of memory?
Stack
What is the lowest level of memory?
Text
The data section of memory is split up into:
Uninitialized and Initialized data
What are the three process states?
1) Running
2) Ready
3) Blocked
What can cause a process to enter a blocked state?
An interrupt from an I/O device.
What are the 4 sections of memory?
1) Text
2) Data
3) Heap
4) Stack
What is a thread?
A unit of work inside a process
What does the OS use to stay organized?
Process Control Block (PCB)
What is a Process Control Block?
A data structure that holds process information such as instruction address, execution stack, resources, etc
