[Info-vax] VAX VMS going forward

[Arne Vajhøj]

On 7/27/2020 2:33 PM, Bill Gunshannon wrote:
> On 7/27/20 1:57 PM, Arne Vajhøj wrote:
>> On 7/26/2020 4:06 PM, Scott Dorsey wrote:
>>> =?UTF-8?Q?Arne_Vajh=c3=b8j?=  <arne at vajhoej.dk> wrote:
>>>> On 7/25/2020 9:46 AM, Scott Dorsey wrote:
>>>>> =?UTF-8?Q?Arne_Vajh=c3=b8j?=  <arne at vajhoej.dk> wrote:
>>>>>> I also suspect that the actual recovery rate may turn
>>>>>> out somewhat less than 100% if attempted to read them all.
>>>>>> Bad tapes, bad tape drives etc..
>>>>>
>>>>> My experience with nine-tracks is that there is nearly a 100% recovery
>>>>> rate.  Occasionally I'll come across 3M Black Watch tapes that need 
>>>>> special
>>>>> processing, but for the most part one cleaning pass and they read 
>>>>> through
>>>>> fine.
>>>>
>>>> If the tapes were 5 years old, the tape drive was 5 years old and
>>>> the tape drive was used every week, then I would expect nearly 100%
>>>> as well.
>>>
>>> I'm talking mostly 1970s and 1980s tapes.  Most of them stored under 
>>> office
>>> conditions.  Occasionally I get older tapes and newer tape and the 
>>> occasional
>>> attic-stored tape.
>>
>> I was always told that tapes (yes 9 track) should be copied to
>> new tapes after 10 years to avoid risk of data loss.
> 
> As opposed to DAT's which I have seen suffer data loss in as little
> as a month.

My experience was that 60m DAT was good, but that 90m was bad
and 120m (or was it 125m ? long time ago!) was horrible.

Arne