They do a lot of work for each and every bit they save & recall.
Hopefully these links will help illustrate in some small fashion that mechanical disk drives are multidisciplinary devices of extraordinary complexity. I'm pooped! here some great reading for all to enjoy! There's never such thing as half-a-sector being written or filled.
Too many hi or lo signals in series can cause readback trouble, so the signal is encoded. The data is encoded in a way to ensure that there are no long consecutive hi's or lo's and that there is always a transistion to follow. The disk heads and platter see it quite differently. 512-24=488, and these 488 remaining bytes will be written as null or "." or zeros. "Apple II computers rock!" Ok, this is going to fit in one sector. It is up to the OS whether 38 or 67 or 91 or how many bytes are used and considered valid.įor simplicity sake let's say I make a text file that says. 512 bytes, all of those 512 byte are read by the drive and presented to the file system.
Sorry we're home from a vodka party and maybe tomorrow I can explain things more concisely.Ĭlick to expand.Just clarify for me, what do you consider to be a damaged sector, how did it get that way, and what does the magnetic signal look like as it is being read back?īe aware that a sector can not ever be considered full or empty.
It is here, at this point, I say again, that these 3 programs do their magic. A weak signal that the firmware has no idea what to do with. Some may stop writing midway through a "bit-transition" leaving a weak signal in a sector. Understand that when a disk loses power, not all drives stop writing at the end of a sector and wrap things up nicely. Not the square wave you're accustomed to seeing representing digital data. It is important to remember that HDD data is 100% analog in nature and the waveform looks like a sine wave. I've kept an informal log of all this activity, and all the fixed disks are still in service today. Using spinrite (and competitor's products all the same) either re-wrote the sector or triggered the firmware to do so. And in subsequent reads, the firmware would encounter the faulty sector and throw the disk off-line. I've "fixed" many disks with spinrite and co where power was knowingly interrupted. What they do fix is the mis-written signal on the disk itself.
That's just it! Spinrite and competitors will not fix the mis-written data. While HDD Regenerator is OK, its never worked as well as Spinrite for me. And not just me, I know others in corporate IT who have used it countless times with great success.
Certainly better than spending $$$$ on data recovery services.įeel free to use it however you wish, but I've used Spinrite on many disks with great success and very few non successes. Note, sectors are rarely 100% full as they are in 512byte or 4Kb chunks so even when Spinrite cannot read a complete sector there's still a decent chance at least that it got all the relevant data.Īnd, I have used Spinrite on last leg harddisks MANY times and made them readable again to the point where I was able to copy off user data. Spinrite hammers away at those sectors and reads and moves whatever it can. Where Spinrite shines is on disks that have damaged sectors. If any of the data is "incorrectly written" it will be moved off and still be incorrectly written (unreadable). A sector contains the header, data and ECC code. Spinrite has no ability to fix bad data on "a partly (or incorrectly) written sector due to sagging voltage levels".