![]() When we've done all the processing and moving to get them all ready, we fire off that byte.Īt the other end of the cable, when the drive receives the bits, it must go through the reverse process to convert that byte back into a serial bit stream so the disk drive write heads can write it to the disk. ![]() Thus, before we can send a byte in parallel to a disk drive, we have to get those eight bits and line them up, funneling each to a different wire. ![]() We talk about bytes for convenience, but a byte is just a line of eight bits in a row, and ultimately, we have to process each bit separately. Processing Overheadįirst, remember that data is stored and retrieved one track at a time, one bit at a time. At current speeds, parallel transmission has several disadvantages. Isn't parallel more efficient than serial, with more capacity? Not really, and certainly not anymore. We now see this same migration in the interfaces that connect disk drives.Īt first glance, this seems counterintuitive. Laptops have dropped traditional parallel and serial ports in favor of higher-speed Universal Serial Bus and IEEE 1394 ports. So why are vendors dropping parallel interfaces in favor of serial ones, when we need to get data to and from disks faster than ever?įor example, most printers don't even come with parallel ports anymore.
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