Could that be mediated with many read heads at different locations?
It'd probably be mediated with a thicker tape with a thicker head: the thicker the tape, the more "data per inch" passes through the head, which allows bandwidth to increase. That would change the LTO-tape dimensions however, so that probably isn't an option.
Fortunately, by shrinking down the size of data (more data per square mm), the bandwidth necessarily increases. So maybe this technology will have a faster read/write speed than today's tech.
The data on an LTO tape is written in a serpentine manner, or boustrophedon if you prefer, with overlapping series of tracks separated by the servo tracks used to position the head.
I dunno, if multiple heads were worth it, I think it would be common.
The tape does not rewind in this scenario.
It is fairly common for the system to not be able to keep up with the full write speed of the tape. Just as a reminder, LTO7 has a write speed of 300 Mb/s, and filling a 300 Mb/s pipe for five and a half hours is no small task.
There are two ways the system deals with it. First, the drive will slow down the tape to match the data rate. Second, the drive can mark a section of tape as failed and then rewrite that data to the next part of the tape. Instead of rewinding and writing over a section of tape, you’re using up more tape this way.
Tapes, like hard drives and SSDs, come with a certain amount of extra capacity to allow for this as well as other write errors.
> I dunno, if multiple heads were worth it, I think it would be common.
I’m sure that it’s “not worth it”, yes, absolutely. But I don’t see major technical hurdles here.
One technical hurdle would be figuring out how to, say, fill an 800 Mb/s pipe for six hours straight. That’s hard. It gets harder when you realize that a single tape library might have as many as 64 or 80 tape drives. 64 drives, multiplied by 400 Mb/s, is 26 Gb/s.
Returning to the idea of increasing throughput on the drives by adding heads, I'm just doubtful that it would be the best way to improve overall system performance. For alternatives, you can either get engineers to optimize usage of existing drives or buy more drives.