How security holes happen

Chris Angelico rosuav at
Wed Mar 5 16:16:53 CET 2014

On Thu, Mar 6, 2014 at 1:11 AM, Mark H. Harris <harrismh777 at> wrote:
> My first IBM machine was the famous PCjr... booted directly into cartridge
> BASIC, or would optionally boot DOS 2.1 from 5" floppy, where I could
> run, you guessed it BASICA, using the cartridge rom,  or I could optionally
> run DEBUG.COM and code up 8086 machine code (not assembler, mind you).

My first IBM machine (first I used - the first computer I actually
personally *owned* wasn't till this century) was an Epson
XT-compatible. We had GW-BASIC and Q-BASIC, and a much superior form
of DEBUG.EXE that came with, get this, an inbuilt mini-assembler! Yes,
I could do this:

xxxx:0100 mov ah,09
xxxx:0102 mov dx,0109
xxxx:0105 int 21
xxxx:0107 int 20
xxxx:0109 db "Hello, world!",13,10,24

And it'd produce the appropriate bytes. From memory, that would be B4
09 BA 09 01 CD 21 CD 20, followed by the text string. I actually used
that to write seriously-useful programs, like one that helped us keep
track of which treasures we'd picked up in Colossal Caves. (For some
definition of "seriously-useful", anyway.)

> At IBM we were coding Rexx on the VM370 systems, and then Rexx on the
> OS/2 systems; no python, and nothing much else either , oh yes, Turbo BASIC,
> Visual BASIC, and of course BASICA although you could then get it as GWBASIC,
> ... still no python.

I wasn't working at IBM itself, but when Dad switched to OS/2 for our
home business, we switched too. That would have been about 1992; we
used OS/2 2.1 briefly, but got properly into things with Warp 3
(Connect, and I can never remember whether it was red-box or blue-box
- we had the one that came with a Windows license for Win-OS/2). Ooh,
we had the most amazing fun with that... we set up, to quote my older
brother, our very own personal World Wide Web! (Not very accurate, but
that was the big buzz-word at the time, and hey, we did have a LAN.)
And over the ensuing years, we got to know which network cards were
the most reliable - mainly the Realtek ones, we had some RTL8029 cards
that went into so many different computers - and if anything went
wrong with drivers or anything, I'd pop the case and stick in one of
my stand-bys. Either that, or we'd go search for the drivers on
Hobbes, and either download 'em onto a floppy disk or LinkWiz them
across - because one of the very first things we'd put onto any
computer was the comms software that uses a special serial-port or
parallel-port cable to transfer files. Immensely useful, until generic
network drivers got better :)

> Did anyone mention that PCs back in that day were toys. And I do mean toys.
> They were slow, they crashed, their graphics sucked...

Oh no! No no no! Graphics didn't suck for everyone. Maybe they did for
you, you with the horrible CGA card plugged into your TV. Maybe they
did for the people who used the default IBM Monochrome card that
didn't do graphics at all. But no, my dad was forward-looking. He got
the best. He got a Hercules Graphics Card, capable of driving the same
screens the IBM Mono would, but giving us the tremendous capability of
720x348 monochrome graphics! It was awesome! Plus, for text colors we
had black, white, bold black, and bold white, and - get this -
underlined! Nobody else got that.

Yes, those were the days.


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