On 2018-08-07, Martin Gregorie  wrote:

> On Tue, 07 Aug 2018 13:41:10 +0100, NY wrote:
>
>> "Martin Gregorie"  wrote in message
>> news:pkbqqm$386$1@news.albasani.net...
>>
>>>>> Best is to use postal pigeons with those card for data,
>>>>> it is cheaper and faster per GB than the internet ;-)
>>
>> I remember a guy I used to work with at ICL had a sign above his desk
>> saying "Never underestimate the information transfer rate of a
>> truck-load of mag tapes" which is the same principle.
>
> :-)
>
>> That was in the days of reel-to-reel mag tapes that were about 18 inches
>> diameter
>
> Nearer 10.5 inches IIRC, holding 2400ft of 0.5 inch tape.

Yup.

>> Are tapes still used much for computer backups, or has everyone gone
>> over to remote off-site backup onto hard disc?
>>
> I think you'll find LTO cartridges are still quite widely used for
> archival storage.
>
> The cartridges are 102.0 × 105.4 × 21.5 mm × 21.5 mm containing 1/2"
> tape. The latest spec (LTO-8) stores 12TB in each cartridge.

A 4-dimensional cartridge?  No wonder they hold so much data.  :-)

> Bit of a change from the old ICL drives which, IIRC held about 8 MB per
> reel.

Depends on block size.  Short blocks mean that the 0.6-inch inter-record
gaps are longer than the data blocks themselves.  But if you used a
decent block size (e.g. 4K) you could get about 20 MB on a 2400-foot
reel at 800 bpi.  Newer, higher-density drives could do even better.

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