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Definition
| contains all processes residing on the disk that await allocation of main memory. |
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Term
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| indicates whether a task is being executed on the behalf of the user(1) or the kernel(0). when executing a user application it is 1. when executing a the kernel is performing an operation it is 0. |
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| a program that is executing. an active entity that needs resources such as CPU, memory, and files. Progresses sequentially. |
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Term
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Definition
| give a computer a batch of jobs to complete with out interaction from the user. |
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Term
| all i/o instructions are (privileged or non privileged) |
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Term
| interrupts cause a switch to which mode? |
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Definition
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Definition
| program used to limit the amount of time a process can run uninterrupted. |
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Term
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Definition
| software generated interrupt |
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Term
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Definition
| cpu is multiplexed between various programs that are running concurrently. there is an interaction between user & the machine |
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Term
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Definition
| the part of the OS that stays in memory |
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Term
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Definition
| when the process has been created |
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Term
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Definition
| all resources have been allocated except for the cpu. the process is currently waiting for cpu allocation |
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Term
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Definition
| the cpu is allocated to a process |
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Term
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Definition
| process is waiting for an event to occur |
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Term
| terminated(process state) |
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Definition
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Term
| process control block(pcb) |
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Definition
| represents a process. contains information on process state ,program counter. cpu registers, scheduling info(cpu & memory). accounting info. |
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Term
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Definition
| a table containing all of the jobs in the system. |
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Term
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Definition
| chooses one of the new jobs(from the job pool) to bring to the ready state, used every few milliseconds. |
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Term
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Definition
| chooses one of the ready processes (stored in main memory) to execute when the cpu becomes available. |
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Term
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Definition
| used when a job is "executing" but not making any progress. this scheduler removes these jobs from memory. also called when a processor needs to be switched out for another for CPU efficiency. |
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Term
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Definition
| top layer is UI. bottom layer is hardware. each layer is build off the function cals available from the previous layer. API on a very large scale. causes large amounts of overhead. |
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Term
| structure of original unix kernel |
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Definition
| kernel acts as a middle man between hardware and application programs. kernel is very large and contains file system, memory management ,etc. |
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Term
| problems with original unix kernel |
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Definition
| too bloated. makes maintenance and debugging very difficult. |
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Term
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Definition
| massive amounts of overhead is generated from all of the function calling |
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Term
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Definition
| bugs are easily isolated to individual layers. once the lower layers have been debugged, the upper layers can easily be debugged. |
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Term
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Definition
| all non essential components of the kernel have been removed. these components are reimplemented as system & program applications. the items left in the kernel are minimal resource management and message passing. |
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Term
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Definition
| easy to add functionality to, easy to debug. safe, since most items are being run as application processes |
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Term
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Definition
| basic unit of cpu work. part of a process. |
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Term
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Definition
| the system saves the state of the current process ( current instruction, the program counter, etc) and picked up latter after the cause of the context switch has been dealt with. |
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Term
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Definition
| used to get the message queue id of a message queue or make a message queue. returns the id. |
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Term
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Definition
| occurs in message passing. the sender and receiver must know each other's names. |
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Term
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Definition
| receiving process does not care who sent the message. |
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Term
| synchronous message passing(blocking) |
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Definition
| the sender & receiver wait until the msg has been sent/received. |
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Term
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Definition
unlimited- not actually infinite, just really large. producer never has to wait. consumer has to wait for a message to be created.
bounded - fixed size. producer may have to wait for buffer to be emptied(aka their previous messages have been read). consumer has to wait for a message to be created.
none- zero size. sender has to wait for receiver to request data. receiver will wait fro sender to send data. |
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Term
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Definition
| uni-directional. can't be accessed outside of fathering process. generally used to communicate with children. once communication ends, the pipe dies. |
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