{"id":43,"date":"2005-07-20T14:28:21","date_gmt":"2005-07-20T05:28:21","guid":{"rendered":"https:\/\/regex.info\/blog\/2005-07-20\/43"},"modified":"2005-07-20T14:33:04","modified_gmt":"2005-07-20T05:33:04","slug":"memory-lane-looking-at-code-i-wrote-almost-20-years-ago","status":"publish","type":"post","link":"https:\/\/regex.info\/blog\/2005-07-20\/43","title":{"rendered":"Memory Lane — looking at code I wrote almost 20 years ago"},"content":{"rendered":"

I had the most interesting peek into my past recently, when the\nRootstown Water Company asked me to look at a small<\/span> issue with their\nbilling software. I originally<\/span> wrote it back in 1986 (19.5 years ago!).\nThey're still using it, unaltered except for one bill-formatting routine\nwhich needed to be updated for a new<\/span> printer some years back.<\/p>\n\n

It's really pretty much in the state I left<\/span> it, except that the machine\nis running Windows 3.11<\/span> now (it had been running only DOS 2.11 when I was<\/span>\nthere — I know<\/span> the version number because they still have the original\n“IBM DOS 2.11” manual). Yes, they still boot Windows 3.11<\/span> every\nday (with win<\/b> at the end of autoexec.bat<\/b> — remember those\ndays?)<\/p>\n\n\n\n\n\n

My code was written in C<\/b> and compiled with the Mark Williams C\ncompiler version 3.0.6 (has a copyright<\/span> date of 1982-1985). You really<\/span> got\na lot<\/span> with this compiler. It was modern<\/span> enough at the time to be on 5.25"\nfloppies instead of 8" floppies. Everything came on two 5.25" floppies,\nincluding all system header files, the pre-processor, compiler, assembler,\nlinker, all libraries, a debugger,<\/span> some Unix utilities (make, egrep,\nbanner, etc.), and even an editor — MicroEMACS. In fact, they even had\nenough room (on the two 5.25" floppies, mind you) left over for the source\nto MicroEMACS. My, how times have changed.<\/p>\n\n

The problem that had cropped up in the software was reduced\nfunctionality in a non<\/span>-critical reporting area due to some integer\noverflow. They shouldn't have run into the problem in the first place, but\nhad neglected to run some maintenance programs for a few<\/span> years. A log file<\/span>\ngrew unchecked, and its size eventually eclipsed the 16 bits the compiler\nalloted to an INT. (Had I had<\/span> the foresight to make it an UNSIGNED INT, the\nproblem would not have shown itself in my lifetime, so I accept<\/span> some of the\nblame \ud83d\ude42 )<\/p>\n\n

The fix — making one variable UNSIGNED — would have been easy except\nthat for whatever reason, the compiler no longer worked properly. They had\nmoved everything to new hardware from backups after a disk<\/span> crash some years\nback (to the 333MHz Celeron 64<\/span>-meg of memory they're using now), and\nperhaps that has something to do with it. The build<\/span> process would end with:<\/p>\n\n

LD: \\bin\\libc.olb(printf.o): bad reloc type 41<\/pre>\n\n
Although the compiler's two-volume hardcover manuals have 20 pages\ncovering build errors, I could<\/span> find nothing about “bad reloc”\nof any type, much less type 41.<\/p>\n\n
They still had the full backup of the C:<\/b> drive that I made<\/span> on\n9\/6\/86, on nine floppies, and in theory I could<\/span> have pulled the compiler\nfrom that, but either the 19-year-old floppies no longer worked, or the\nfloppy drive didn't work. After inserting a floppy<\/span> into the drive, seeing\nthat the drive reported an error, and pulling it back out, it was hard not\nto notice the thick layer of dust the process had imparted onto the disk.\nEven after putting in many floppies, they still came out with somewhat of a\nlayer<\/span> of dust, making me wonder if the “dust” is really disk\nmaterial flaking off.<\/p>\n\n
 So, I decided<\/span> to move to a more<\/span> modern OS where I could<\/span> use modern\ntools to rebuild things. They had some Win2K computers for other reasons,\nso that was good enough. I installed<\/span> the wonderful<\/b> DJGPP<\/a> system (gcc, gmake, and lots\nof GNU tools like bash and emacs) and recompiled there. Considering that my\nsource was written in pre-ANSI C, and considering that I had<\/span> written it\nwhen I had<\/span> no considerable programming experience, well, there were a lot<\/span>\nof little things to clean up. I used many<\/span> of gcc's command-line options to\nturn on a lot<\/span> of warnings (including -Wall<\/b>), and so spent a few<\/span>\nhours going through everything updating to ANSI-C and cleaning up unused\nvariables and dangerous typecasts.<\/p> 
In doing the heavy linting, a few\nbugs turned up and were fixed, although I seriously<\/span> hesitated to change\nanything about how things worked, since they'd been using it as is for 19\nyears. My brother<\/a> suggested PC Lint<\/a> would be more insightful than\ngcc, as he says it's unparalleled in its ability to point out\n“issues”, but the aforementioned desire not to change much —\ncombined with my limited time and energy — caused me to set this idea\naside.<\/p>\n\n
It's always a little scary to look at old code, but this is by far the\noldest code that I know<\/span> to still exist. (I wrote<\/span> some very nifty stuff, in\nFORTH<\/a> no less, to control\na flow-cytometer<\/a>\nduring the early 80s when I worked<\/span> at a medical school<\/a>, but I don't<\/span> think it's still\nbeing used.) It certainly felt odd to look at it, since I knew<\/span> I wrote<\/span> it\nall (the one formatting routine aside), yet I remembered<\/span> nothing about\nit.<\/p>\n\n
In once sense I was pretty happy with the code. Even though it was\nwritten in 1986 before “Y2K” was on anyone's mind (or, at least\nnot yet on my mind), I still<\/span> engineered it to work fine through the end of\n2079. The DOS on<\/span> the system now (likely the version that came with Windows\n3.11<\/span>) isn't so graceful about dates: files I edit<\/span> today show up with the\ndate “7-20-105”.<\/p>\n\n
In some other senses, I shake<\/span> my head about some of my programming\ndecisions. The way I<\/span> grouped things into files was very dorky, particularly\nWRT header files. Rather than have FOO.C's declarations in FOO.H, I tended<\/span> to replicate the needed declarations in each file that needed it. And my use<\/span> of global\/extern variables was... unsound.<\/p>\n\n
People tell me “hey, but it works”, and the current issue\naside, it has been working quite well for more than 19 years, but “it\nworks” has always been only the most basic starting point to measure\nsuccess, not the ending point. I would<\/span> certainly do it quite differently\nnow, but then, I'd charge<\/span> a lot<\/span> more than $5\/hr to do it!<\/p>\n","protected":false},"excerpt":{"rendered":"
I had the most interesting peek into my past recently, when the Rootstown Water Company asked me to look at a small issue with their billing software. I originally wrote it back in 1986 (19.5 years ago!). They're still using it, unaltered except for one bill-formatting routine which needed to be updated for a new printer some years back.<\/p> 
It's really pretty much in the state I left it, except that the machine is running Windows 3.11 now (it had been running only DOS 2.11 when I was there -- I know the version number because they still have the [...]","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/posts\/43"}],"collection":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/comments?post=43"}],"version-history":[{"count":0,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/posts\/43\/revisions"}],"wp:attachment":[{"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/media?parent=43"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/categories?post=43"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/regex.info\/blog\/wp-json\/wp\/v2\/tags?post=43"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}