IMPORTANT IN CLASS NOTES:-

Fri, Jan 30th:

~Absent due to preparation for exam.~

Wed, Jan 28th:

We covered I/O processing today. Investigating the difference between memory mapped I/O and I/O mapped I/O. We also explored the termed DMA( direct memory access ) , Cycle Stealing, Dual Port Memory and Local Buffers. A new terminology I have learned is "SPOOLING"; which stands for Simultaneous Peripheral Operations On-Line. In short, meaning multitasking.

Mon, Jan 26th:

Memory Protection & Interrupts. A 'segment' is known as a logical unit of same or different sizes while a 'page' is purely hardware of the same size. Interrupt consist of hardware and software. An asynchronous interrupt is something not in control or not expected. In contrast, a synchronous interrupt is set by the processor itself. Thus, knowing when it occurs.

Fri, Jan 23:

Today we learned about protection in the OS.Divided to two modes, 1) Supervisor, 2) User. The supervisor mode allows more access while the non -previlage mode is allowed less access to the OS. The reason for having protection in the OS is to avoid normal users to harm the operating system.How does the OS know which mode it is in? Using a bit set to 1( supervisor ) or 0 ( user ). The bit is located in a Processor Status Register.

Wed, Jan 21:

~ Class was cancelled. Professor not feeling well. ~

Mon, Jan 19:

~ Martin Luther King Day. No class ~

Fri, Jan 16:

Finite State Machine. Consist of 3 main states of 'READY', 'RUN', and 'WAIT'. A "RUN" often means that a process is using the CPU at that time. A "READY" is define as a process having all resoruces ready to be used except the CPU while a "WAIT" state means that a process is waiting for some other resource other then the CPU.RUN and READY can go back and forth while a RUN can turn into a WAIT state. However, from a WAIT state, the process has to go through the READY state before getting to RUN again.

Wed, Jan 14:

Designer/Implementer View. A monolithic model is one big system and consist of single address space while a non-monolithic model has multiple address space and being more flexible.

Mon, Jan 12 :

Functional view of operating system. Real time systems described as highly efficient and very specific. Example: ATM machines and Airline ticketing system. Another term learned is "embedded", meaning built into larger systems.

Fri, Jan 9 :

Defining hardware and software. Individual roles in operating system. Hardware being known as the "naked iron" and a basis of all computation while software is the operating system extended from the hardware capabilities to form the inner core which is the kernal and system services which surrounds the core.

Wed, Jan 7 :

An introduction to operating system. "Why study operating systems?" , to get a better understanding of total hardware and software environments in which we work. "What is an operating system?" , program modules which governs the control of hardware and software resources.