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Which direct memory access channel is used for the floppy controller?
From http://www.brainbell.com/tutors/A+/Hardware/Direct_Memory_Access_DMA.htm "DMA channels use the same rules as IRQs. Just as with the 8259 chip, DMA availability soon became a problem because an insufficient number of channels was available. A second DMA chip was added for 286-based computers. Just like the second IRQ chip, these two are cascaded, allowing a total of eight DMA channel assignments (usually referred to simply as DMA channels). The floppy disk drives on all computers use DMA channel 2."
An ECP parallel port requires the use of what channel?
dma channel
How do you copy music on a floppy?
Use a floppy drive, drag and drop the files you want. The space you have though will be extremely limited, as your using a floppy drive
What is the floppy drive of the MacBook Pro?
No Macintosh has included a floppy drive since the release of the iMac G3 in 1998. If you need to use a floppy disk, you will have to purchase an external USB drive.
What was the first computer to use a floppy drive?
The Mac
Where is the 3 and a half Floppy disk drive on an Dell Inspiron 1520?
The Dell Inspiron is not equipped with an internal or external floppy drive. If you want to use floppies with it, you'll have to purchase an external USB floppy drive.
Is it possible to use floppy disk without using Direct Memory Access?
DMA or Direct Memory Access is the process of getting memory (RAM) without using the CPU. It is turned on based on the program you are running. It is used for things like making sounds while a game is running or for moving data from a floppy and hard drives into RAM. So the program you are running will determine if DMA is used, it does not matter if it is a floppy.
What is the role of drive b?
Drive B is reserved for use with a(n additional) floppy drive
What is DMA structure?
Using interrupts driven device drivers to transfer data to or from hardware devices works well when the amount of data is reasonably low. For example a 9600 baud modem can transfer approximately one character every millisecond ( 'th second). If the interrupt latency, the amount of time that it takes between the hardware device raising the interrupt and the device driver's interrupt handling routine being called, is low (say 2 milliseconds) then the overall system impact of the data transfer is very low. The 9600 baud modem data transfer would only take 0.002% of the CPU's processing time. For high speed devices, such as hard disk controllers or ethernet devices the data transfer rate is a lot higher. A SCSI device can transfer up to 40 Mbytes of information per second. Direct Memory Access, or DMA, was invented to solve this problem. A DMA controller allows devices to transfer data to or from the system's memory without the intervention of the processor. A PC's ISA DMA controller has 8 DMA channels of which 7 are available for use by the device drivers. Each DMA channel has associated with it a 16 bit address register and a 16 bit count register. To initiate a data transfer the device driver sets up the DMA channel's address and count registers together with the direction of the data transfer, read or write. It then tells the device that it may start the DMA when it wishes. When the transfer is complete the device interrupts the PC. Whilst the transfer is taking place the CPU is free to do other things. Device drivers have to be careful when using DMA. First of all the DMA controller knows nothing of virtual memory, it only has access to the physical memory in the system. Therefore the memory that is being DMA'd to or from must be a contiguous block of physical memory. This means that you cannot DMA directly into the virtual address space of a process. You can however lock the processes physical pages into memory, preventing them from being swapped out to the swap device during a DMA operation. Secondly, the DMA controller cannot access the whole of physical memory. The DMA channel's address register represents the first 16 bits of the DMA address, the next 8 bits come from the page register. This means that DMA requests are limited to the bottom 16 Mbytes of memory. DMA channels are scarse resources, there are only 7 of them, and they cannot be shared between device drivers. Just like interrupts the device driver must be able to work out which DMA channel it should use. Like interrupts, some devices have a fixed DMA channel. The floppy device, for example, always uses DMA channel 2. Sometimes the DMA channel for a device can be set by jumpers, a number of ethernet devices use this technique. The more flexible devices can be told (via their CSRs) which DMA channels to use and, in this case, the device driver can simple pick a free DMA channel to use. Linux tracks the usage of the DMA channels using a vector of dma_chan data structures (one per DMA channel). The dma_chan data structure contains just two fields, a pointer to a string describing the owner of the DMA channel and a flag indicating if the DMA channel is allocated or not. It is this vector of dma_chan data structures that is printed when you cat /proc/dma
Can i use a floppy disk in a zip drive?
No. Zip drives cannot read floppy disks, and cannot be used on a traditional floppy controller.
Why cant you have drive B on PC?
The B: drive was originally used back in the days when having two floppy drives was common. A: and B: are reserved for floppy drive use.
what is the role of b?
Drive B is reserved for use with a(n additional) floppy drive
