15 Jul
2012
15 Jul
'12
2:57 p.m.
Rick Murphy wrote:
> >At 06:12 AM 7/15/2012, Jerome H. Fine wrote:
>
>> Rick Murphy wrote:
>>
>>> (For anyone who really cares about TECO-8, I've got a version that
>>> works well with ANSI terminals, including PuTTY.)
>>
>> Does that include a VT100?
>>
>> Will it also work on ANSI terminals with more than 24 lines and / or
>> 132 columns?
>
> Yes, VT100. Since it's basically the VT52 support ANSI-fied it'll work
> on any VTxxx terminal. Unfortunately, only 80x24. It would be very
> difficult to expand that due to the memory requirement for a larger
> screen buffer.
How much memory is available for a program under OS/8?
The memory required for a screen buffer for the VT100 within the KED
variants for RT-11 is only a minor problem even when running under
RT11FB or using Kex.SAV under RT11XM. When Ked.SAV is
initiated by VBGEXE and the full 64 KB is available, any problems with
respect to insufficient memory disappear for a straight DEC VT100.
The above seems counter-intutive since normally a user would expect
a full virtual program designed to run under RT11XM would have more
available memory than a program designed to run under RT11FB.
If anyone is interested, I can provide a detailed explanation.
In my particular situation when I do any development, I almost always
run a four system jobs under RT-11 for a KED variant which is explicitly
designed for that purpose. In addition to having all the features that are
available when running as a background job, the additional requirement
is the minimum possible low memory usage. Recent versions of KEX.SAV
released by DEC required 801 words of low memory for system jobs.
Reducing that to 449 words required a bit of imagination. However,
starting with KEX.SAV as the base still greatly restricted the memory
available for the screen buffer and other work space. Switching to
Ked.SAV as the base increased the work space from 16KB to
to almost 40KB or much more than double. If anyone is interested,
the details are also rather interesting to a software addict. Note that
the details are specific to RT-11 which has specific restrictions on
system jobs as opposed to RSX-11 and TSX-Plus which treat all
jobs in essentially the same manner as far as available memory is
concerned.
As for "terminals" which have more than 24 lines and / or 132 columns,
even 40K bytes is not very much memory for a "terminal" with 100 lines
and 200 columns, but it is sufficient. At present, the maximum number
of lines available for an ANSI (VT100 compatible) "terminal" is 60 lines
(as far as I know) and around 200 columns. That requires a 12 KB
screen buffer which is best allocated on demand and as required
rather than setting aside 12 KB all the time and wasting what is not
used. However, code for that solution is also a problem in the KED
variants.
Jerome Fine