[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [TASS] Xmas Data Munching / Issues
Thanks to Chris for a nice discussion of how CVS works.
Hardware guys have struggled with this problem for 1500-2000 years.
Possibly longer. Over the last 100 years or so there has been a good way
to make it work.
The idea is that there is a set of master tracings. There is also a
revision procedure and a sign off procedure for making a revision. Mostly
one person must sign off changes. Multiple copies of the master tracings
can be made. If you are building an Empire State Building the plumbers
have a copy, the electricians have a copy, the carpenters have a copy,
etc.. They all mark up their drawings to show the changes that they have
made in the field. The marked up drawings are sent back to the drafting
room and there the changes are added to the master drawing set. Any time
you want you can get a new set of prints with the latest changes. A great
deal of attention is paid to who has what version of the drawings. Usually
there are rubber stamps the show that this particular drawing set is for
bid purposes or released for construction, etc. When I built the addition
to the house there were two sets of drawings signed by myself and the
contractor. This helps reduce law suits.
Nothing gets built exactly like the drawings. In the case of my addition,
the spiral stair did not fit, and there was no place to get hot air from
the first floor to the second. This required some big box structures in
the pool room.
I am aware that all this is on computers these days. The ideas remain the
same. Computers make it easier to keep a paper trail of changes. (I just
keep all the old master drawings in a pile in case I ever need to
reconstruct what was done in the past.)
A control system like CVS is much like this. Except in the software case
there can temporarily be many different Empire State Buildings. In the
hardware case there is only one. The hardware case is a little differentin
in that at any time you can go out to the real Empire State Building and
see what is actually there. (Well this is actually not so easy. Lots of
things get covered up. Jimmy Hoffa, for example.) It is common practice
in building projects to try to produce an "As Built" set of drawings at the
end of a project.
As I say, it took thousands of years for engineers to work out this
process. The real "break through" came when it became possible to make a
direct copy (I think the old sun made blue prints were the first) of a
drawing without the errors introduced by a copy maker.
It seems to have taken a while for software to get to this point. I once
supervised 17 systems programmers (1970). They insisted on operating as
individuals and would simply not submit to any kind of control or system.
It was very frustrating for an engineer used to a work structure. I was
just told that software did not allow any structuture. Ha!
I very much endorse working under a control system like CVS. I don't care
which one is used. I would lean toward the simplest one available with the
fewest options. This will make it easier for us all to learn it and to
follow. We probably don't need something as complicated as that Microsoft
would use on Windows 2000 or Lockheed would use for a military system.
Note that I am not trying to "control" anything but chaos. It is not my
plan to use such a thing to control the work that is done. The sole
purpose is to control the quality of the work. I think we all want that.
Seems to me that we need a "Drafting Room" head. Some one person needs to
step forward and say "I will pick a system and will sign off on revisions".
How about it, Chris?
I might add that I am running a very simple system for the Mark IV
drawings. The master drawings are on the computer. Any time I want I can
run off a set. However, there is only one "Master" set. From time to time
I will run off a fresh drawing. The procedure then is to find the previous
"Master" for that drawing. I cross out "Master" (Usually written in red
ink so that I can identify it" and initial it. I then write "Master" on
the new copy and date and initial it. The date allows sorting out the
latest copy if there happens to be two Master copies laying around. I
actually have a rubber stamp for this purpose left over from a company I
started in 1956. It is usually easier to just write master on the drawing
than to find the rubber stamp.
Note that I will shortly start sending hardware out into the field. When I
do, it will come with a complete set of drawings. You all will make
changes. Some will be private to your equipment. Others we will want to
make common to all the systems. For these I will need for you to send me
marked up drawings. I will then updated the masters and send out ECO
(Engineering Change Order) kits to all the systems with new drawings and
parts to be added. One expects to do this in engineering.