FDD 3.5": small FAQ... :)

Greetings, O venerable All! ================== begin of file "FDD35faq.C" ================== - How does a modern 3.5" drive work and work? The main internal elements of the drive are the floppy frame, spin- efficient motor, head unit with drive and electronics board. Spindle motor - flat multi-pole, constant speed rotation speed 300 rpm. Head drive motor - stepper, worm, gear or belt drive. To identify the properties of a floppy disk on the electronics board near the front At the end of the drive there are three mechanical pressure sensors installed - chica: two - under the protection and recording density holes, and the third - behind the density sensor - to determine the moment of lowering the dis- chum salmon A floppy disk inserted into the slot goes inside the floppy disk frame, where it the protective curtain is moved, and the frame itself is removed from the stopper and falls down - the metal ring of the floppy disk when this rests on the spindle motor shaft, and the lower surface floppy disks - on the lower head (side 0). At the same time freeing there is an upper head, which is pressed under the action of a spring to the top side of the floppy disk. On most drives, the frame lowering speed is not limited in any way. low, causing the heads to cause a noticeable impact on surfaces floppy disks, and this greatly reduces the period of their reliable operation. In someSome drive models (mostly Teac) provide slow-down microlift for smooth lowering of the frame. To extend the period For the service of floppy disks and heads in disk drives without a microlift, we recommend sulking when inserting a floppy disk, hold the diskette button with your finger water, preventing the frame from lowering too sharply. On the spindle motor shaft there is a ring with a magnetic lock - lump, which at the beginning of engine rotation tightly grips floppy disk ring while centering it on the shaft. In the majority disk drive models, the signal from the floppy disk lowering sensor causes short-term start of the engine in order to capture and center it vaniya. The disk drive is connected to the controller using a 34-wire ca- white, in which the even wires are signal wires, and the odd wires - general. The general interface option involves connecting to the controller has up to four disk drives, the option for IBM PC - up to two. In general, the drives are connected completely in parallel. each other, and the drive number (0..3) is set by jumpers on electronics board; in the version for IBM PC, both drives have a measure 1, but are connected using a cable in which the signals are bor (wires 10-16) are inverted between the connectors of the two disk- Dov. Sometimes pin 6 on the floppy drive connector is removed, playing In this case, the role of the mechanical key. The drive interface is quite simple and includes selection signalsdevices (four devices in the general case, two in the variant for IBM PC), starting the engine, moving the heads one step, recording enable, read/write data, as well as information formation signals from the disk drive - the beginning of the track, a sign of turning the heads to the zero (external) track, signals from sensors etc. All the work of encoding information, searching for tracks and sectors, synchronization, error correction is performed by the control rum Standard HD (High Density) floppy disk format ity) - 80 tracks on each side, 18 sectors of 512 bytes on the path. Condensed format - 82 or 84 tracks, up to 20 sections 512 bytes each, or up to 11 1024 bytes each. - What are the most common problems with floppy drives? - Connecting the interface cable backwards. At the same time, in When the power is turned on, the access indicator immediately lights up to the drive, which normally should not happen. Short-term switching on Operating in this mode is usually not dangerous for the drive and the controller. ra, however long-term operation can lead to failure output buffers. - Failure of the disk lowering sensor or poor contact of the extreme pro- water of the interface cable transmitting the "Disk Change" signal (disc change). In this case, the system does not respond to changing the floppy disk - when reading a directory, the directory of the previous floppy disk is displayed, and whenWhen attempting to write, the file structure on the disk is most often destroyed. chum salmon - Failure of the density sensor or write protection. In the first case, floppy disks of one of the densities (DD) stop being read and written or HD), in the second the recording becomes permanently available or not accessible regardless of the position of the latch on the floppy disk. . ================== end of file "FDD35faq.C" ================== Best regards, Felix. [I.ZX]