Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
69 Cards in this Set
- Front
- Back
|
Contains software (programs) and Hardware (physical machine and electronic components)
|
Computer System
|
|
|
It is part of the computer system (software) and manages all hardware and software. Controls everything including who can use the system and how the system is used.
|
Operating systems
|
|
|
What are the four essential Subsystem Managers?
|
Memory, Processor, Device, and File Managers
|
|
|
allows the user to communicate with the operating system. Unique to each operating system AND may vary between versions
|
User command interface
|
|
|
Monitor resources continuously, enforce policies determining: who gets what when, and how much. Allocate and deallocate resources when appropriate.
|
Manager Tasks
|
|
|
Not always present, but is in all modern OS with this capability. Manages communications between users, protocols, etc.
|
Network Manager
|
|
|
Manager responsible for devices, channels and control units (printers, drives, etc.)
|
Device Manager
|
|
|
Manager responsible for Central Processing Unit (CPU). Tracks process status (an instance of program execution).
|
Processor Manager
|
|
|
Manager responsible for main memory
|
Memory Manager
|
|
|
Manager responsible for program and data files, compilers, etc.
|
File Manager
|
|
|
In charge of Random Access Memory (RAM)
|
Main Memory Management
|
|
|
Four responsibilities of Main Memory Management
|
Preserve space in main memory occupied by the OS. Check validity and legality of memory space request. Setting up of memory tracking table (tracks usage of memory by sections. Deallocating of memory to reclaim it.
|
|
|
Two responsibilities of Processor Manager
|
Handle jobs as they enter the system. Manage each process within those jobs.
|
|
|
Four responsibilities of Device Management
|
Choosing most efficient resource allocation method, allocating, starting, and deallocating the device.
|
|
|
Three responsibilities of File Managers
|
Enforcing user/program resource access using predetermined policies, controlling user/program mod restrictions (Read only, write read, create, delete), Allocate (open and close) file resources.
|
|
|
theorized in 1965 by an Intel Exec, this stated that computing power rises exponentially. Every 18-24 months = twice the capacity (number of transistors).
|
Moore’s Law
|
|
|
Five categories of Operating Systems
|
Batch, Interactive, Real-time, Hybrid, Embedded
|
|
|
Two distinguishing features of OS Categories
|
Response time and how data enters system.
|
|
|
System where everything is entered at once and processed at once. Entered serially without user interaction. Efficiency measured by throughput (amount done in amount of time)
|
Batch System
|
|
|
System that has faster turn around than batch systems. Introduced to provide fast turnaround when debugging. Time-sharing software developed for OS.
|
Interactive System
|
|
|
System where reliability is key, fast and time limit sensitive. Used in time critical environments (space, airports, industrial control). Must be 100% responsive, 100% of the time.
|
Real-time System
|
|
|
Two types of Real-time Systems
|
Hard - risk total system failure. Soft - suffer performance degradation, but not total failure.
|
|
|
System that is a combination of batch and interactive. Accepts and runs batch programs in the background with light interactive load.
|
Hybrid System
|
|
|
Operating systems with computers placed inside other products. Adds features and capabilities. Requirements: perform specific set of programs, not interchangeable, small, only necessary components included. ie, car monitoring.
|
Embedded System
|
|
|
Defined as a single instance of execution of a program
|
Process
|
|
|
wasted memory inside a partition
|
Internal Fragmentation
|
|
|
wasted memory between partition blocks
|
External Fragmentation
|
|
|
The table for tracking pages that tracks the size of the job and the memory location where its Page Management Table (PMT) is stored.
|
Job Table (JT)
|
|
|
The table for tracking pages that tracks the page number and corresponding page frame memory address.
|
Page Management Table (PMT)
|
|
|
The table for tracking pages that tracks the location for each page frame and the free/busy status.
|
Memory Map Table (MMT)
|
|
|
In paged memory allocation this determines the line distance from beginning of its page to where an INDIVIDUAL PROGRAM LINE is within the frame. (A relative value)
|
Displacement (offset of a line)
|
|
|
Translating a line’s relative address into absolute address.
|
Address Resolution
|
|
|
an excessive amount of page swaps between main memory and secondary storage and occurs due to temporary page removal that are do not last long and are called back quickly after removal. It can occur both within and across jobs and produces inefficient operation
|
Thrashing
|
|
|
|
Peripherals/io Devices
|
|
|
when several logical records are grouped within one physical record.
|
Blocking
|
|
|
separate from the buffer, this device was developed by moving offline the operations of card reading, printing, and “punching.”
|
Spooling
|
|
|
an interim storage area that works as a temporary holding place. As the slow input device reads one record, the control unit places each character of the record into this
|
Buffer
|
|
|
where programs consist of self- contained, reusable modules called objects, each of which supports a specific function, but which are categorized into classes of objects that share the same function.
|
Object Oriented Design
|
|
|
the primary part of the operating system that remains in random access memory (RAM) and is charged with performing the system’s most essential tasks, such as managing main memory and disk access.
|
Kernel
|
|
|
the component with the circuitry, the “chips,” to control the interpretation and execution of instructions.
|
CPU
|
|
|
a large machine—in size and in internal memory capacity. The IBM 360, introduced in 1964. Very large and expensive
|
Mainframe
|
|
|
a computer developed to meet the needs of smaller institutions, those with only a few dozen users. Satisfied the needs of large schools and small colleges.
|
Mini
|
|
|
computers developed for government and scientific use to crunch lots of numbers like carrying out military operations and weather forecasting.
|
Supercomputer
|
|
|
was developed to offer inexpensive computation capability to individual users in the late 1970s. Single user status.
|
Microcomputer
|
|
|
Powerful microcomputers developed for use by commercial, educational, and govern- ment enterprises. Typically networked together, used for cad and massive math computations.
|
Workstation
|
|
|
powerful computers that provide specialized services to other computers on client/server networks.
|
Server
|
|
|
the processing time required by a device prior to the execution of a command
|
Overhead
|
|
|
the concept of loading many programs at one time and sharing the attention of a single CPU.
|
Multiprogramming
|
|
|
only one program fit in memory at a time. If a program doesn’t fit in memory it doesn’t run. If it does, only it can run and the rest of the memory is unused.
|
Single User Contiguous
|
|
|
one partition for each job. Because the size of each partition was designated when the system was powered on, each partition could only be reconfigured when the computer system was shut down, reconfigured, and restarted. Thus, once the system was in operation the partition sizes remained static.
|
Fixed Partitions
|
|
|
available memory is still kept in contiguous blocks but jobs are given only as much memory as they request when they are loaded for processing.
|
Dynamic Partitions
|
|
|
With this memory allocation scheme, the Memory Manager relocates programs to
gather together all of the empty blocks and compact them to make one block of memory large enough to accommodate some or all of the jobs waiting to get in.
|
Relocatable Dynamic Partitions
|
|
|
sometimes referred to as garbage collection or defragmentation, is performed by the operating system to reclaim fragmented sections of the memory space.
|
Compaction
|
|
|
only a portion of each program is stored in memory, it gives users the appearance that their programs are being completely loaded in main memory during their entire processing time. Removed the restriction imposed on maximum program size by moving pages at will between main memory and secondary storage.
|
Virtual Memory
|
|
|
the process of moving a page out of main memory and into secondary storage so another page can be moved into memory in its place.
|
Swapping
|
|
|
the set of pages residing in memory that can be accessed directly without incurring a page fault.
|
Working Set
|
|
|
based on the idea that the system can use a small amount of expensive high- speed memory to make a large amount of slower, less-expensive memory work faster than main memory. This memory is small in size and faster than main memory. When used data or instructions are stored here, memory access time can be cut down significantly and the CPU can execute instructions faster.
|
Cache Memory
|
|
|
behavior observed in many executing programs in which memory locations recently referenced, and those near them, are likely to be referenced in the near future.
|
Locality of Reference
|
|
|
Before a job is loaded into memory, it is divided into parts called pages that will be loaded into memory locations called page frames. Based on the concept of dividing each incoming job slots of equal size.
|
Paged Memory Allocation
|
|
|
combination of segmented and demand allocation offing the logical benefits of segmentation and the physical benefits of paging. This allocation scheme doesn’t keep each segment as a single contiguous unit but sub- divides it into pages of equal size, smaller than most segments, and more easily manipulated than whole segments. Therefore, many of the problems of segmentation (compaction, external fragmentation, and secondary storage handling) are removed because the pages are of fixed length.
|
Segmented/Demand Allocation
|
|
|
What kind of memory allocation did MS-DOS use?
|
First Fit Algorithm
|
|
|
What were the 5 design goals of Windows?
|
Extensibility, Portability, Reliability, Compatibility, and Performance.
|
|
|
What kind of memory allocation did Windows use?
|
Virtual Memory (FIFO)
|
|
|
3 Advantages of Unix
|
Portability, Powerful utilities, Application Device Independent
|
|
|
Who developed Unix?
|
Ritchey and Thompson
|
|
|
What kind of memory allocation did Unix use?
|
Demand Paging/Least Recently Used
|
|
|
What kind of memory allocation did Linux use?
|
Virtual Memory/LRU
|
|
|
What was the purpose of Linux
|
Maximize Intel 80386 microprocessors limited capabilities
|
|
|
Who developed Linux?
|
Linus Torvald 1991
|
