[Info-vax] And another one bites the dust....

[Dan Cross]

In article <620ec8dc$0$697$14726298 at news.sunsite.dk>,
Arne Vajhøj  <arne at vajhoej.dk> wrote:
>On 2/17/2022 4:38 PM, Dave Froble wrote:
>> On 2/17/2022 2:17 PM, Arne Vajhøj wrote:
>>> Sometimes the decision is to migrate. Sometimes the decision is
>>> not to migrate.
>>>
>>> Not to migrate is probably the most common.
>> 
>> If it ain't broke, don't fix it.
>> 
>> How many times do things get "fixed" anyway?
>
>Pretty often. Until something else is broken.

The "if it ain't broke don't fix it" argument also ignores
externalities.

And it's not like mainframe-based systems aren't being
upgraded; there are costs associated with that.  How many
IBM 370/158s are still running in production?  3090s?
9021s?

>>> But the question comes up again and again. If the question comes
>>> up every 3 years and it is 20% migrate 80% keep, then after 24
>>> years 87% has migrated.
>> 
>> Statistics doesn't work that way.  It is not cumulative.  If the ratio 
>> is 20/80, then every time it's 20/80.
>
>Statistics work that way.
>
>20% attrition every 3 years means that after 24 years 87% is gone.

First cycle in year 0, then 8 more cycles terminating in the 24th
year?  Yeah, that's about 87%.

	- Dan C.