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PCjs: Virtual IBM PC

pcjs.org

71 pointsvmorgulis18 comments

  format a:

does an endless loop.

Edit: oh, going back I got an JS popup:

  Unable to restore disk 'PC-DOS 2.00 (Disk 1): 
  sector (CHS=0:1:0) out of range (9 changes applied)

After pressing the reset button:

  Non-System disk or disk error
  Replace and strike any key when ready

I had to press load disk A button, to start fresh. Quite impressive.

And then I just found out to load Windows 1 with mouse support. Wow. Made my day. Epic!

It's a major point to make sure errors are properly emulated as well. Same issue was dealt with in VMware Workstation as well, which managed to behave accurately for devices such as floppy disks.

Last month, I was cleaning some stuff out in the garage and found my IBM PC green screen monitor had fallen off the shelf and smashed on the floor. I had bought the PC back in 1983 or so.

The end of an era for me, I guess.

The weird thing is I thought DOS at the time was complicated. It looks trivial today, and I wonder why multiple people did not create independent operating systems from scratch for the PC.

CRobots (programming game):

http://tpoindex.github.io/crobots/pcjs/crobots-pcjs.html

Pretty cool - and accurate. In the IBM Model 5150, there was a bug in Microsoft's floating-point math routine of the PC's BASIC ROM chip. If you ask the system to divide 0.01 by 10, it displays 9.999999E-4, instead of the correct answer of 0.001.

You can see this by launching into BASIC from the simulation and trying:

print 0.01/10

compare this to for example:

print 0.01/100

Dating myself here, but I still remember coding up quicksort programs in computer science class on these things, back in high school in the 80s.

That's not really a "bug": http://0.30000000000000004.com/

I know the point that you're making, but I'm not sure that the simulation has the 8087, or that the BASIC ROM would use it if it did. The software implementation has some interesting quirks:

print 0.1/10

0.01

print 0.01/10

9.999999E-4

print 0.01/5

0.002

print 0.001/10

0.0001

print 0.1+0.2

0.3

A>Basic

  10 PRINT "HELLO"  
  20 GOTO 10

<F2>

HELLO x inf...

20 seconds of nostalgic entertainment

"Type 10 spacebar print spacebar shift-quote H E L L O shift-quote and press Enter."

BEEP BEEP BEEP

https://www.youtube.com/watch?v=ZhNX_tyBvq0

Don't forget the semi-colon on the end of line 10 to remove the line break and spread the message across the whole screen!

Notice: remove your headphones before opening the page

A friend of mine tried PCjs with classic BASIC games before.

http://blastar.in/dell/poker/

http://blastar.in/dell/slots/

http://blastar.in/dell/bj/

You just need to turn caps lock on because they are case sensitive. But they are BASICA compiled games from the 101 BASIC Games book.

If you load the OS2 image and put DOS 2 disk 2 in the drive you can play Bill Gate's epic game "DONKEY.BAS". He was still bragging about that at the MS company meeting circa 2005 or so.

Something nostalgic about the speed of the display updates on old PC's like that. Typing 'dir' and watching things fly in line by line.

Can new versions of Word still open the .DOC files from Windows 1.0, such as on this emulator?

I believe that this is a different file format that would require a converter. The file extension was eventually changed to .WRI for this reason.

I'm sad that the music in MUSIC.BAS doesn't seem to work. No PC Speaker support, maybe?

Can anyone use the OS/2 module? It just errors for me across several browsers.

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