GDB for the course “System Programming (CS609)” will be open on Thursday 20th Feb, 2014 and it will be closed on Friday 21th Feb, 2014.

[Sonia Naz]

Graded Discussion Board Announcement

Dated: Feb 11, 14

Dear students, Graded Discussion Board for the course “System Programming (CS609)” will be open on Thursday 20th Feb, 2014 and it will be closed on Friday 21th Feb, 2014. Discussion Topic "The methods of DMA mode transfer are limited to protected mode programs." Support or contradict this statement with solid reason. Read the instructions carefully before sending your comments: GDB will have weight-age of 5% of your total subject marks. Your discussion must be based on logical facts. You should post your comments on the Graded Discussion Board & not on the Regular MDB. Both will run parallel to each other during the time specified above. Your comments should be relevant to the topic i.e. clear and concise (Maximum 100 words). Books, websites and other reading material may be consulted before posting your comments. (Do not copy the material as it is.) No extra time will be given for discussion. You cannot participate in the discussion after the due date or through e-mail.

[RANA USMAN]

Aray yaar pora Google chaaan mara  pata nai ye  topic google py b nai ha.

kisi site py is ka hint nai mila......aur yaha jo hona tha disscuss wo ho chuka ab apna apna labo te submit karo....

Allah Allah khair sallah...

[badarqa shakoor]

g g abdul rauf bahi yematerial jo ap ne dia maine b dekha but iska connection dma transfer mode se kaisy howa ye bata dain?? plz

[badarqa shakoor]

bilkul sahi kaha ap ne RANA USMAN  pta nae kaha se sir ye topic utha k dia hai

[Hirabatool]

DMA Modes
• Block Transfer
• Single Transfer
• Demand Transfer

Protected  mod  konsa ha :O lectures  me to DMA  k  ye modes diye hoe hn 

[Asim Raza]

PIO

[Kaneez Fatima]

Protected Mode Memory Addressing Has features designed to enhance multitasking and system stability, memory protection and support for virtual memory.

[Kaneez Fatima]

DMA has three transfer modes: 

1. Burst or Block Transfer Mode: the DMA controller transfers one block of data at one time. It is useful for loading a program or a data file but it keeps the CPU inactive for a relatively long period of time. 

2. Cycle Stealing Mode: the DMA controller accesses the system bus by BR (Bus Request) and BG (Bus Grant) signals. The DMA controller sends BR, transfers 1 byte of data then it sends BG. The control of the system bus is continuously obtained and released. The CPU is idle for less time than in the Burst Mode but the data transfer takes more time. 

3. Transparent Mode: it takes the most of the time because the DMA controller transfers data only when the CPU does not use the system bus. It is called transparent because the CPU continuously works on other tasks so the DMA does not interrupt it.

[Hirabatool]

In computing, protected mode, also called protected virtual address mode,[1] is an operational mode of x86-compatible central processing units (CPU). It allows system software to use features such as virtual memory, paging and safe multi-tasking designed to increase an operating system's control over application software.[2][3]

When a processor that supports x86 protected mode is powered on, it begins executing instructions in real mode, in order to maintain backwards compatibility with earlier x86 processors.[4] Protected mode may only be entered after the system software sets up several descriptor tables and enables the Protection Enable (PE) bit in the control register 0 (CR0).

[adnan]

very very tough gdb