I believe they have overestimated the cost of using 3.5" floppies, probably to make themselves look better by comparison.
They give the cost as $211,172, but that's the cost to buy a 1 TiB pack of floppies. Their own storage cost is per-month, so to get the equivalent cost for floppies you need to also divide by the expected useful lifetime of a floppy disk. I did a web search for "floppy disk lifetime" and the internet [1] told me "I’ve seen numbers saying the lifespan of floppy disks is three to five years. But I’ve also seen numbers that claim they can last ten to twenty years or even indefinitely."
If you assume floppy disks have an expected lifetime of 5 years, you can amortise the cost across that time, bringing the cost per TiB-month down to a nice reasonable $3,520.
You've got to wonder how it would work if taken to the extreme: rack after rack of floppy drives filling an entire data centre providing a glacially-slow S3 service.
Can you imagine the noise? It would be... glorious.
They're 5.75 x 4.25 x 0.75 inches. So if you mount them vertically like in high-density storage arrays, you can fit 25 of them into the width of a rack, about 7 rows from the front to back. So... about 175 per layer that is about 4 RU high including the space for the controller board. You can fit 10 of these layers in a standard rack, for 1,750 floppy drives total per rack.
Let's see... that's 2.52 GB per rack! Seek times are variable depending on the floppy drive model, but 250 ms is approximately correct for the average. So about 7,000 IOPS total per rack. Not too shabby!
A decent sized data centre might have 1,000 racks. So a "cloud-scale" floppy drive object storage system might have 2.52 TB of raw storage. However, you have to divide that by three for the redundant copies, so we're back to 840 GB of usable storage capacity per floor, but with an impressive 7M IOPS.
To put things in perspective, that's directly equivalent to a single modern laptop SSD drive in terms of both capacity and IOPS. Except that the latency of the SSD is 5000x lower.
Since this is a write-only service, it doesn't actually matter if the disk stops working, or even ceases to exist. Therefore we may be able to estimate the lifespan as infinite.
There may also be no need to purchase more than one disk. In fact taken to its logical conclusion there is no need to purchase any disk at all - but of course that brings us all the way to the S4 business model itself.
I don't think comparing a service like S4 to a non-existing disk is fair. Especially in enterprise software, I often get the requirement that the data is reliably written. I can easily point an auditor to the S4 service contract and SLAs to prove we fulfill this. A bespoke arrangement of floppy drives and shredders might pass if the auditor's having a good day. But removing the disks entirely? That will never fly.
Since we have multiple points of data for lifespan, perhaps we should be computing a weighted average between them?
Going by gut feel: 3-5 years sounds like "pretty likely", let's give that 95% of the weight, at 4 years for simplicity. 10-20 years would be nice, but really, how much tech lasts that long? Not much. How about 4.9999999% at 15 years. And the remaining can go to "indefinitely", which seems pretty darn unlikely, so it has 0.0000001% weight.
(4*95+15*4.9999999+∞*0.0000001 / 100) = ∞
I guess we can ignore the monthly cost ¯\_(ツ)_/¯ I applied weights to things, so this is Bayesian, and we all know that's always right.
Just roll them in a nice soft blanket. I have one that keeps me warm even in plain winter. We can add a hot chocolate cup and that should do the trick.
Given my own experience with 3.5" floppies in the past often yielded lifetimes in single digit months, I would say any estimate of years needs to have a very large error margin, and you need to use RAIF.
But at 25kbps sustained write (inc optimistic disk juggling) it'd take 463 days to write 1TB. If that's your comparison number, you'd need to factor in 17 drives running in parallel to write 1tb in February. And a robot, or 6 people to handle disks. And 14m³ archive space.
And double all that if you want redundancy.
But the abacus beads could store rotational data. There's at least 8 bits of data there, more if you can put some time in. That's free real estate there.
i believe there is an opportunity in the market for an advanced data storage technology to support writing huge volumes of information to a single 3.5" floppy, provided the legacy constraint of offering a read operation can be dispensed with.
They give the cost as $211,172, but that's the cost to buy a 1 TiB pack of floppies. Their own storage cost is per-month, so to get the equivalent cost for floppies you need to also divide by the expected useful lifetime of a floppy disk. I did a web search for "floppy disk lifetime" and the internet [1] told me "I’ve seen numbers saying the lifespan of floppy disks is three to five years. But I’ve also seen numbers that claim they can last ten to twenty years or even indefinitely."
If you assume floppy disks have an expected lifetime of 5 years, you can amortise the cost across that time, bringing the cost per TiB-month down to a nice reasonable $3,520.
[1] https://blog.storagecraft.com/data-storage-lifespan/