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Speed is very specific to the particular drive. While the platters inside are rotating at a constant angular velocity, the modern hard drive tries to record data at a constant data density per unit length of head travel along the track, so the data rate varies as the head moves from inside of the disc, where the lowest block numbers are, to the higher numbered blocks that are at the edge. The data rate further is going to be varied by the encoding applied to the data so it can be recorded reliably, with forward error correction and spectrum spreading data added, along with the encryption if used on the drive, so the rate will be varying around a small value that is compensated for by the buffer built into the drive, typically something like 64k, 128k or 256k, depending on the drive type and desired application. Then you get variations caused by the drive having to move the heads, and after moving it has to check it is on the correct track, by reading some sector data, then writing when the right sector is below the head, and then reading the next sector data before the write. Also complicating things id the drive remapping bad sectors, so that you can have the next logical block to be read or written not being actually in the next physical sector, but it has been relocated to a spare block ( interspersed through the drive surface during manufacture and hidden, like so many of the internal operations, from the outside, so the drive appears as a perfect drive while in reality it is very unreliable, relying heavily on error detection and correction to get the data back and show it to the outside) so there has to be a head movement and then a few cycles to get the correct track. Tracks are so close together that the only way to get the correct one is to go to the approximate position and then move slowly while reading to get the correct track and then wait for the right block to go under the head.Reading can be worse, as the drive often has to use error correction to get the data back despite noise, or do multiple reads to reconstruct the data from best guesses from the reads. Too many and it ( secret sauce again) will decide to reallocate the data on the block to a spare track when idle, and mark the block internally as relocated and not usable. Thus a drive which appears as perfect can go from working to unreadable very fast as the spares are used up, and the drive no longer can swap out growing defects.But to the original question, so long as the data is coming in at a lower rate than the worst write ability the drive can keep up and write it, if it comes in the drive will buffer to the point where the buffer is full, then simply discard some data ( mostly the last lot) and return an error code of it not being able to write the data. Reading the data rate will be set by the drive, requesting faster will simply result in the drive returning as not ready until the buffer is filled with data, and the read will stall.
1. The hard drive when ''blank'' contains only 0's?
2. Two identical camcorders will record at an equal rate?
3. Two synchronous recordings on the two individual hard drives will show the same amount of space used on the hard drives?
4. Both recordings will show the same amount of time recorded?
would the information ''fill'' the hard drive at a constant rate?
Quote4. Both recordings will show the same amount of time recorded?Yes. Unless data is actually dropped, the recorded time should be identical.
Just another caveat about the drive, as it comes from the factory, is actually blank. The one platter has been taken and had the head assembly ( the slots in the top covered by an adhesive cover and the label cover the holes) precisely aligned while a so called servo track is written on it. Then this servo track is used during test to write the rest of the tracks as the drive is used to scan itself. The drive itself uses a special firmware loaded in the factory to do this work, then the drive has the latest firmware version loaded as a final step before it is packed, the special firmware generates the first bad block tables, stored on the drive platter itself. The final firmware ( loaded by a small 6502 clone inside the drive that handles the initial startup of the drive by loading all the registers of the main processors and loading the software they need into them) is only run the first time when you power up the drive. This then will do a read after write on each write ( what it has to do in all cases anyway) to actually verify the data has been recorded, using a separate read head on the surface a little downstream of the write head.The attached is a drive I scrapped this last week, where the one head separated from the head carrier ( never found it, just little bits of silicon dust) in operation, and disintegrated the drive surface on both sides. Lucky I had a backup on a drive that in turn also turned out to have issues, though I was able to recover the data I needed using a Puppy install on a DVD. Windows would not read the drive, but Linux had no issues, and SMARTMON stopped a little way in with unreadable sectors.
Thank you , I got agreement on the important answer from you.
So just to confirm, if I was on planet X that was half the mass of the earth, and you was on earth, and we started to record synchronised , at the end of recording we would both have to agree we have just recorded the exact same amount of time as each other?
Answer to the new question: The recorded times would be different, but by an amount that is too small to measure.
are you saying that in dual playback one will run slower than the other one slightly?