DOS ain't dead

FPC 2.6.2 released (Announce)

posted by Laaca , Czech republic, 18.03.2013, 12:00

Today I quickly tried current 2.6.2 version.
I can't recommend it at all for DOS programmers.

1)
There still remains the old pain of all 2.x.x FPC line for DOS - the bug (18113) in generating the alternate segment prefic code in generated assembler and machine code.
It is in all OS targets but in windows, linux etc. are the OS services invoked via DS selector, in DOS it is via FS selector. So it occurs only in DOS.
This bug is already fixed in 2.7.1 but the fix was not backtraced into 2.6.x line. I don't understand why.

2)
Again occured weird problems with environment settings when shelling into DOS.
This time it will be harder to trace. Last time it occured always but now I saw this problem only under Windows 98. In FreeDOS I haven't noticed the problem but very probably exist also there. To be short, under W98 it cuts some environment variables. Look here (done in IDE --> command shell, then typed "set")
D:\WINDOWS\COMMAND.COM
P=D:\WINDOWS\TEMP
PROMPT=$p$g
winbootdir=D:\WINDOWS
COMSPEC=D:\WINDOWS\COMMAND.COM
CTSYN=D:\WINDOWS
PATH=D:\WINDOWS;D:\WINDOWS\COMMAND;C:\BAT;C:\KOMP
windir=D:\WINDOWS
BLASTER=A220 I5 D1 H5 P330 T6


But should be (i.e. if I type "set" not in IDE session)

TMP=D:\WINDOWS\TEMP
TEMP=D:\WINDOWS\TEMP
PROMPT=$p$g
winbootdir=D:\WINDOWS
COMSPEC=D:\WINDOWS\COMMAND.COM
CTSYN=D:\WINDOWS
PATH=D:\WINDOWS;D:\WINDOWS\COMMAND;C:\BAT;C:\KOMP
windir=D:\WINDOWS
BLASTER=A220 I5 D1 H5 P330 T6



3)
And the very new problem is the fatal IDE unstability. IDE almost always starts only first time. I start the IDE, compile and run the program (f.e. Hello.pas) and close IDE. But when I want to start IDE again it crashes with this error message:

Exiting due to signal SIGSEGV
FPC General Protection Fault at eip=006EDE95
eax=90909090 ebx=0000002A ecx=00000088 edx=00000000 esi=008F11F8 edi=0083B504
ebp=008C0CA0 esp=008C0C90 program=C:\TP\FPC262\BIN\GO32V2\FP.EXE
cs: sel=00A7 base=8470A000 limit=008FFFFF
ds: sel=00AF base=8470A000 limit=008FFFFF
es: sel=00AF base=8470A000 limit=008FFFFF
fs: sel=00D7 base=00000000 limit=0010FFFF
gs: sel=00D7 base=00000000 limit=0010FFFF
ss: sel=00AF base=8470A000 limit=008FFFFF

Call frame traceback EIPs:
$006EDE95
$005BD905
$005BCD84
$005BC83D
$005BC7F8
$00308AF8
$0030B9F4
$0002DB50
$0002DC5A
$00002040


It occurs in both my systems - in FreeDOS and in Windows 98. To be able to start IDE again in FreeDOS I have to reboot the computer. Under W98 is enough to restart the DOS command prompt.

4)
I don't know if it has some meaning but why in the "Memory sizes" in IDE is "Stack size: 0" and "Heap size: 0" ?

So, unfortunately 2.6.2 is a bad version for DOS. The unability to restart the IDE is the killer bug.

I recomend to stay with version 2.4.2 or, of course, with 1.0.10

---
DOS-u-akbar!

Complete thread:

• FPC 2.6.2 released - marcov, 26.02.2013, 10:09 (Announce)
  • FPC 2.6.2 released - Rugxulo, 27.02.2013, 10:49
    • FPC 2.6.2 released - marcov, 28.02.2013, 13:46
      • FPC 2.6.2 released - Rugxulo, 28.02.2013, 20:43
        • FPC 2.6.2 released - Rugxulo, 02.03.2013, 18:57
          • FPC 2.6.2 released - marcov, 03.03.2013, 00:21
            • FPC 2.6.2 released - Rugxulo, 03.03.2013, 02:36
              • FPC 2.6.2 released - marcov, 04.03.2013, 22:23
          • FPC 2.6.2 released - Rugxulo, 14.03.2013, 17:16
            • FPC 2.6.2 released - Rugxulo, 28.03.2013, 00:35
    • FPC 2.6.2 released - rr, 03.03.2013, 21:08
  • FPC 2.6.2 released - Laaca, 18.03.2013, 12:00
    • FPC 2.6.2 released - Rugxulo, 19.03.2013, 00:08
      • FPC 2.6.2 released - Arjay, 19.03.2013, 01:48
      • FPC 2.6.2 released - Laaca, 19.03.2013, 11:40
        • FPC 2.6.2 released - Rugxulo, 21.03.2013, 17:26