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Old August 29th 04, 01:11 PM
jim
 
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Leland C. Scott wrote:
"Frank Gilliland" wrote in message
...

On Sat, 28 Aug 2004 20:30:50 GMT, jim wrote
in :


Leland C. Scott wrote:

"Twistedhed" wrote in message
...


Do or can you write and design software programs?


I did for class projects when I was working on my computer science


degree.

The biggest program was an integrated DOS utility for reading disk
parameters, viewing the raw sector data, showing what disk clusters


were

used by any file on the disk, and finally a disk defragmentation


function.

The program featured pop-up overlapping menus, hot keys, and mouse


control.

It was written in C++ and took me about 2-1/2 months to write working


on it

around 15 to 20 hours per week, design - test - debugging. And after


all

that it was specifically written for a 720K floppy disk so the


professor

could test it without killing his hard drive in case of bugs. All that


was

for a project for a class I took in operating systems. I think mine was


the

only one that worked and also handled subdirectories too. Even the 20+
something year old class computer geek wiz, and the professor's pet


student

no less, couldn't do it. I got the "look" from him in the hallway one


day at

the start of the next semester.

I haven't really gotten in to doing Windows programming, it's event


driven

verses procedural coded. That's a totally different animal. Windows
programming is a real pain, and complex if you really want to take full
advantage of the system. For simple programs that don't need a lot of


fancy

wiz-bang features Visual Basic is a good choice to use. The other


choices

are Visual C++, C#, or Java. The last three are object orientated


languages.

That could be a big chuck to bite off and learn for somebody who hasn't


done

any programming at all.

I've also done some Intel assembly language programming - 8080 and X86,


and

VAX-11 assembly too. Assembly language programming is to computers like
Morse Code is to Ham Radio. Now that I think about it the first


computer I

had was a Radio Shack TRS-80 with16K of memory. The first assembly


language

program I wrote, in Z80 assembly, was to translate text on the screen


into

Morse Code by keying the relay contact used to control the


record/play-back

function of the cassette recorder used for program storage.

jeez leland you are showing your age i fixed the hardware problems
associated with the 8080 processor on several military related programs.
hell we used uv ovens to clear the memories of chips.
the simulators the air force used drum drive technology and if the sims
were having a problem we took out an alan key and physically moved the
read/write heads until it worked. the damn drum drives were used in
grumman a6 aircraft also. hehehe looking back its a wonder that stuff
actually worked.



Do you remember "bubble memory"?



Sure do Frank, and all the hoopla about it becoming the next best thing in
memory storage. I've even run across some magnetic core memory cards. A
customer I visited, of the company I work for, had some they needed to get
repaired because they used it in an old minicomputer controlling some of the
equipment in the plant. I saw them in their electronics shop waiting to get
sent out to the computer manufacturer. The cores where about the sign of a
pin head, and the core select, and sense wires, had to be 40 gage, like hair
thin size. I think the core planes had to be hand built because of the tiny
size of the cores and the wire used. The memory cycle times from what one of
my books say was around 1 microsecond. And these were used in the mainframes
of the day. Compare that to present day memory chips!


now that leland mentions it they were also used on the simulators and
were literally called core memory. things weighed a ton and needed to be
reset very often using front panel switches.
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Old August 29th 04, 04:34 PM
Lancer
 
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On Sun, 29 Aug 2004 01:20:38 -0400, "Leland C. Scott"
wrote:

I didn't use any OS calls at all. The only BIOS functions I used were direct
calls to read/write absolute disk sectors. Everything else I had to write
from scratch. As simple as the DOS file system was there was still a lot to
handle. What made thing more interesting was all I had to work with was a
Windows 98 machine. That made thing more complicated because Windows always
wanted to create long file names which messed things up a bit when you
format a disk. I had to put extra routines in to the code to filter that
crap out so when the disk was defragmented I had wiped all the Windows file
system extensions out, thus generating a valid DOS disk.


Windows 98 runs on a DOS kernel, so all windows 98 systems run on a
"valid" DOS disk. Edit your msdos.sys and turn your GUI off. Or just
make yourself a boot disk and format the drive.
  #23   Report Post  
Old August 29th 04, 04:59 PM
Leland C. Scott
 
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"Lancer" wrote in message
ews.com...
On Sun, 29 Aug 2004 01:20:38 -0400, "Leland C. Scott"
wrote:

I didn't use any OS calls at all. The only BIOS functions I used were

direct
calls to read/write absolute disk sectors. Everything else I had to write
from scratch. As simple as the DOS file system was there was still a lot

to
handle. What made thing more interesting was all I had to work with was a
Windows 98 machine. That made thing more complicated because Windows

always
wanted to create long file names which messed things up a bit when you
format a disk. I had to put extra routines in to the code to filter that
crap out so when the disk was defragmented I had wiped all the Windows

file
system extensions out, thus generating a valid DOS disk.


Windows 98 runs on a DOS kernel, so all windows 98 systems run on a
"valid" DOS disk. Edit your msdos.sys and turn your GUI off. Or just
make yourself a boot disk and format the drive.


Yeah, however I didn't feel like rebooting the computer 20 - 30 times going
through the design - test - debug routine each time I worked on the project.
The complier runs under Windows, but the defrag program runs under DOS. When
the program failed I ended up with a wrecked disk format. It was easier to
format the disk in a DOS window and just filter the long file name directory
entries out during the defrag process. It was rather easy to do anyway since
the long file name extension is done by using extra directory entries, 11
characters per entry, following the normal DOS directory entry for a given
file. The long file name directory entry is marked with an invalid set of
attribute bits that can't be set by the user under any condition so its easy
to detect. Also it just so happens that DOS ignores the directory entries
with the invalid attribute bit settings. The long file name ability using
Windows is a real hack on the part of Microsoft. Each directory entry uses
32 bytes, and only 11 are used, the old DOS 8 dot 3 file name format, the
rest is wasted. Enough of these directory entries are used as required until
there is enough 11 byte blocks to hold the long file name.

--
Leland C. Scott
KC8LDO

Wireless Network
Mobile computing
on the go brought
to you by Micro$oft


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