1. EDS LAYOUT ?
I'am trying to figure out the layout and constuction of EDS
but the documentation is very poor in discribing the construction
and layout.
I don't understand what this -4 offset means ?
-- block of table headers:
-- -4: allocated size of this block (for possible
How the tables and table headers tie into the database
main header ?
How did RDS come up with value 19 pointer in the following code
in db_create routine ?
-- 3:
put4(19) -- pointer to tables
I would like to understand the internal layout of the
database better than the confusing discription at the
top of the database.e. The description does not explain
how the tables and headers are linked together.
Bernie
2. Re: EDS LAYOUT ?
- Posted by euman at bellsouth.net
Dec 07, 2001
Hello Bernie,
You must be thinking the same thing I have for some time now.
I've been studying some other languages to draw a conclusion how I would like to
re-write EDS for my personal use.
How about MUMPS or M for short.
Hierarchical data base facility. Mumps data sets are not only organized along
traditional sequential and direct access
methods,
but also as hierarchical trees whose data nodes are addressed as path
descriptions in a manner which is easy for a programmer
to master in a relatively short time.
Maybe by looking at the Mumps to C translator I can replicate the MUMPS
architecture. NOT THE LANGUAGE ITS SELF!
Mumps is so terse typed you'd need a miracle to translate only a subset of this
OLD lang.
If you ask me I dont understand why companies pay programmers $40+ hr to program
in Mumps. It would seem that
TCO "total cost of ownership" is out the Window <"hehe" on that subject...
Even still, my laptop probably cruches numbers faster than the machines that run
Mumps.
as for your question, Im not entirely sure but it looks as if Rob is just
telling us where to look for the starting offset to
the first table entry.
Euman
euman at bellsouth.net
>
>
> I'am trying to figure out the layout and constuction of EDS
> but the documentation is very poor in discribing the construction
> and layout.
> I don't understand what this -4 offset means ?
> -- block of table headers:
> -- -4: allocated size of this block (for possible
>
> How the tables and table headers tie into the database
> main header ?
>
> How did RDS come up with value 19 pointer in the following code
> in db_create routine ?
>
> -- 3:
> put4(19) -- pointer to tables
>
> I would like to understand the internal layout of the
> database better than the confusing discription at the
> top of the database.e. The description does not explain
> how the tables and headers are linked together.
>
> Bernie
3. Re: EDS LAYOUT ?
Bernie Ryan writes:
> I'am trying to figure out the layout and constuction of EDS
> but the documentation is very poor in discribing the construction
> and layout.
Yes, it's very cryptic. I would really need to draw a big diagram
or something to explain it. When I get into EDS again, I'll see if
I can make things clearer, but I think 90% of EDS users have
no motivation to try to tinker with it at that level.
> I don't understand what this -4 offset means ?
> -- block of table headers:
> -- -4: allocated size of this block (for possible
The size of a block is stored in the 4 bytes before
the logical start of the block, just like some C compilers
do when you malloc() a block of memory. i.e. you get
a pointer to a block of 100 bytes, but 104 bytes is actually allocated,
with the number 100 being stored just before where the
returned pointer points. (this stuff is hard to explain
without drawing a diagram.)
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
