Board index » delphi » The FAMOUS divide by zero bug in the CRT unit

Paul Griffiths

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

The FAMOUS divide by zero bug in the CRT unit

I have only just come across this bug as I/we have been using "slow"
computers so far (233MHz MMX) ;-)

The situation regarding fixes and patches is very unsatisfactory.

Some of the fixes are specific to version 7 or 7.01.  My system reports V7.0
in help about.  Does the newer version report 7.01?

I looked at the "re-writing CRT unit" messages and got lost in the spaghetti
of threads!  :-)

We use Turbo Pascal with HNC and HND students so we are not generally
talking rocket science but they do all use the CRT unit!

Does anyone have any simple advice?

regards

Paul Griffiths

P.S.  What is Borland's official position on this?

 
Ing. Franz Glase

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:The FAMOUS divide by zero bug in the CRT unit


Quote
Paul Griffiths wrote:

> The situation regarding fixes and patches is very unsatisfactory.

What are you looking for? A ready made cooking recipe?
Quote

> Some of the fixes are specific to version 7 or 7.01.  My system reports V7.0
> in help about.  Does the newer version report 7.01?

No, look on the file dates with the DOS C>dir command. Some files have
a 7.01 time stamping.
Quote

> P.S.  What is Borland's official position on this?

They say: TP 7 is not made for the faster PII computers. If you want
to use TP or the self made executables, try to apply one of the patches
which are found on:
http://www.geocities.com/SiliconValley/2926/tp.html

Of course they do not say this literally...

Franz Glaser

Scott Earnes

Delphi Developer
Wed, 18 Jun 1902 08:00:00 GMT

Re:The FAMOUS divide by zero bug in the CRT unit


Quote
Paul Griffiths wrote:
> I have only just come across this bug as I/we have been using "slow"
> computers so far (233MHz MMX) ;-)

> The situation regarding fixes and patches is very unsatisfactory.

> Some of the fixes are specific to version 7 or 7.01.  My system reports V7.0
> in help about.  Does the newer version report 7.01?

You sound like you're confusing your DOS version (7.0 is Win 95 or 95A) with
your TP version.  There are two versions of TP7 -- 7.00 and 7.01.  Both are
essentially the same, in that the compiler can use units compiled in either
version.  The only difference is that 7.01 had some bugfixes made to the
runtime code.  As I own both 7.00 and 7.01 runtime code distributions, I can
tell you that the CRT code is not one of the units that was modified -- a file
comparison shows that the source is identical.  Any claims for a patch to be
specific to version is one that relies on patching TURBO.TPL (or TPP.TPL for
protected mode), which IMHO is not a good way to go about patching (even where
source is not available, the CRT unit could be extracted, patched, then
reinserted to the TPL file).

Quote
> I looked at the "re-writing CRT unit" messages and got lost in the spaghetti
> of threads!  :-)

Indeed.

Quote
> We use Turbo Pascal with HNC and HND students so we are not generally
> talking rocket science but they do all use the CRT unit!

> Does anyone have any simple advice?

I just went to Franz Glazier's TP page and looked at the various links for one
that would work for me.  I needed it to repair a program that was being run by
someone on a PII-450, but I has of yet not needed it for my own use (although,
as I write, my nifty new PII-400 is en route.  :-)

Quote
> regards

> Paul Griffiths

> P.S.  What is Borland's official position on this?

Entirely disinterested, it seems.

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