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15 Cards in this Set
- Front
- Back
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Computer System |
Software (programs) Hardware (tangible machine, electronic components) |
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Operating System |
Manages all hardware and software. Controls every file, device, section of main memory, and processor. |
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Operating System Managers |
Device, File, Memory, Processor |
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Minimum Manager Functions |
Monitor system resources Enforce policies (who gets what, when, how much) Allocate Deallocate Must have cohesion |
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User Interface |
Communication mechanism. Users interact directly with OS (and managers) in non-networked environment by issuing commands. |
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Main Memory (RAM) Management |
Allocate and deallocate memory. Shields part of OS in RAM from alteration. |
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Processor Management |
Tracker of each job, process, and thread. Process: program's "instance of execution" (Math prob., single job w/ several processes, each process does part of the overall prob.) Reclaims CPU for reallocation when process is finished or max computation time has expired. |
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Device Management |
Connect every device available on system, efficiently as possible. Devices: printers, keyboards, monitors |
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Device Driver |
Software w/ detailed instructions required by the OS to: 1. Start device 2. Allocate 3. Use 4. Deallocate |
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File Management |
Enforces restrictions on who has access to which files. |
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Types of OS |
Batch Interactive Hybrid Real-Time Embedded Ranked by response time and how data enters system. |
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Batch system |
Entered in whole and in sequence: One job at a time, no other job can start processing until the job already there is done. Input relied on punched cards -- tape Efficiency measured in throughput: 1. number of jobs completed in a given amount of time 2. minutes, hours, days |
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Interactive system |
Allow multiple jobs Response w/ turnaround times in seconds -- minutes Complex algorithms to share processing power. |
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Real-time system |
Used in time-critical environments like spacecraft, hospitals, airport traffic control. Data must be processed with strict time limit. Hard: total system failure if predicted time deadline is missed. Soft: suffer performance degradation due to missed deadline |
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Hybrid system |
Combination of batch and interactive (BI) Appear interactive (users enter mult. jobs/ processes w/ fast responses): 1. Accept -- Run batch in background when interactive load is light. Loves free time: 1. Between high and low-demand usage of system |
