relax: Segmentation fault

Wasting time doing more “research” on old GCC, and thanks to suggestions I thought that in addition to the old 1.x stuff, but I should include my old favorite 2.5.8, and the stalled 2.7.2.3, and the EGCS Pentium improved GCC fork. I figured re-treading on old ground with the xMach/OSKit build on x86_64 should be safe/quick & easy.

My cross chain fails when trying to build libgcc.a How annoying but I already have one, so I bypass it, and GCC then tries to build the crt (c runtime library startup code) and that fails too!

../binutils-990818-bulid/gas/as-new crtstuff.S -o crtstuff.o
Segmentation fault

I’m using GCC 12.2.0 on Debian 12. Ok maybe I’ve finally hit drift, so let me try some other binutils. binutils-2.10.1, binutils-2.14. I had originally been lying saying I’m a Dec Alpha running either OSF or Linux as it matches the size & endian alignment, but no dice. I found out about the ‘linux32’ command that’ll fake it’s environment as an i686 processor to fake out a lot of builds. But the same result over and over. So, I break down and fire up GDB.

(gdb) r
Starting program: /root/src/xmach/binutils-2.14-bulid/gas/as-new crtstuff.S -o crtstuff.o
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x0000555555592ef0 in md_estimate_size_before_relax (fragP=fragP@entry=0x555555668fa8, segment=segment@entry=0x555555668730) at ../../binutils-2.14/gas/config/tc-i386.c:4441
4441      return md_relax_table[fragP->fr_subtype]->rlx_length;
(gdb) bt
#0  0x0000555555592ef0 in md_estimate_size_before_relax (fragP=fragP@entry=0x555555668fa8, segment=segment@entry=0x555555668730) at ../../binutils-2.14/gas/config/tc-i386.c:4441
#1  0x000055555558bce2 in relax_segment (segment_frag_root=0x555555668f30, segment=segment@entry=0x555555668730) at ../../binutils-2.14/gas/write.c:2266
#2  0x000055555558c39c in relax_seg (abfd=<optimized out>, sec=0x555555668730, xxx=0x7fffffffe960) at ../../binutils-2.14/gas/write.c:659
#3  0x000055555559b01f in bfd_map_over_sections (abfd=0x55555565e030, operation=operation@entry=0x55555558c370 <relax_seg>, user_storage=user_storage@entry=0x7fffffffe960)
    at ../../binutils-2.14/bfd/section.c:1101
#4  0x000055555558b501 in write_object_file () at ../../binutils-2.14/gas/write.c:1565
#5  0x000055555556e288 in main (argc=2, argv=0x5555556302d0) at ../../binutils-2.14/gas/as.c:924
(gdb) quit

The whole issue revolves around md_relax_table! I’d seen a ‘fix’ where you add in a pointer, and it’ll satisfy GCC and sure it’ll compile. Years ago, I had #ifdef’d it out until when I needed it, but the real answer is to embrace 1989 and set the compiler flags to “-std=gnu89”

I can’t help but think at some point soon 1989 will be removed as it’s only wierdos like me building this stuff.

Just as the old Unix error status of sys_nerr has been removed for ‘reasons’ so may as well amputate all the old code:

-  if (e > 0 && e < sys_nerr)
-    return sys_errlist[e];

Nothing much you can do about it, Linux isn’t trying to be Unix anymore.

64/32

In the end it doesn’t seem to matter. OSkit fails to build:

i586-linux-gcc -c -o base_multiboot_init_cmdline.o -MD -DHAVE_CONFIG_H  -DOSKIT_X86 -DOSKIT_X86_PC -DINDIRECT_OSENV=1 -I. -I../../oskit-20020317/kern/x86 -I../../oskit-20020317/kern/x86/pc -I../../oskit-20020317/kern/x86/dos -I../../oskit-20020317/kern  -I- -I../../oskit-20020317/oskit/c -I.. -I../../oskit-20020317 -nostdinc -Wall  -O2 -g  ../../oskit-20020317/kern/x86/pc/base_multiboot_init_cmdline.c
i586-linux-gcc: Internal compiler error: program cc1 got fatal signal 11
make[1]: *** [../../oskit-20020317/GNUmakerules:124: base_multiboot_init_cmdline.o] Error 1

And surprisingly mig does build, but Mach does not.

i586-linux-gcc -c   -MD -DLINUX_DEV=1 -DHAVE_VPRINTF=1 -DHAVE_STRERROR=1  -Di386 -DMACH -DCMU -I- -I. -I../../../kernel/libmach/standalone -I../../../kernel/libmach/c -I../../../kernel/libmach -I/root/src/xmach/xMach/object-kern/libmach -I/root/src/xmach/xMach/object-kern/../kernel/generic/libmach/standalone -I/root/src/xmach/xMach/object-kern/../kernel/generic/libmach/c -I/root/src/xmach/xMach/object-kern/../kernel/generic/libmach -I../../../kernel/include/mach/sa -I../../../kernel/include -I/root/src/xmach/xMach/object-kern/../kernel/generic/include -I/root/src/xmach/xMach/object-kern/include -I/root/src/xmach/xMach/object-kern/../kernel/generic/include/mach/sa -nostdinc  -O1 /root/src/xmach/xMach/object-kern/libmach/bootstrap_server.c
/root/src/xmach/xMach/object-kern/libmach/bootstrap_server.c: In function `_Xbootstrap_privileged_ports':
/root/src/xmach/xMach/object-kern/libmach/bootstrap_server.c:90: `null' undeclared (first use this function)
/root/src/xmach/xMach/object-kern/libmach/bootstrap_server.c:90: (Each undeclared identifier is reported only once
/root/src/xmach/xMach/object-kern/libmach/bootstrap_server.c:90: for each function it appears in.)

Needless to say, this is why I don’t use OS X anymore. Not having a 32bit userland basically killed it for me.

I guess the next step is to go ahead with qemu-user mode wrappers to fake it.

Sorry if you were hoping for some great conclusion.

Two things that really annoy me!

Moving homes. again.

First off, I got a new VPS to house this on, size wise, I’d just plain outgrown the old one, even with SquashFS. Over on lowend box, I had spotted this one: LuxVPS

It’s not an AD, just thought the pricing seemed pretty good for 5€. One of the nice things about converting so much of my data to SquashFS is that moving single files is WAY easier to deal with!

Mice in my 1970’s teletype text editor?!

Using Mice with a 1970’s text editor

But editing text files had me facing off some feature of VIM I’d somehow not dealt with that Debian 11 set by default, and that is mouse integration!

CAN YOU BELIVE IT?

Somewhere out there, is people who use a mouse with a VI clone. 

It bares repeating

SOMEONE THINKS YOU NEED A MOUSE TO USE VI.

So much so, it’s the system default.

Good lord.

The fix is to edit /etc/vim/vimrc:


set mouse=
set ttymouse=

Problem solved. Obviously, I’m not going to remember this, but now I can right click/paste the way G’d intended it!

Stale encryption

Old rusty locks

The next source of annoyance is the ancient stunnel 4.17 that I use for altavista.superglobalmegacorp.com. I’m kind of trapped with this setup as it needs to be a 32bit ‘workstation’ OS, and I don’t want to run something as heavy as XP or Vista when NT 4.0 is more than enough. Anyways OpenSSL won’t talk to this ancient encryption, throwing this error trying to do a connection with “openssl s_client -connect 192.168.23.6:443”:

error:1425F102:SSL routines:ssl_choose_client_version:unsupported protocol
Unable to establish SSL connection.

The fix, thanks to dave_thompson_085 is simple enough.

Basically, modify /etc/ssl/openssl.conf and place this at the top:


openssl_conf = default_conf
#
# OpenSSL example configuration file.
# This is mostly being used for generation of certificate requests.
#

then place this at the bottom:


[ default_conf ]

ssl_conf = ssl_sect

[ssl_sect]

system_default = ssl_default_sect

[ssl_default_sect]
MinProtocol = TLSv1
CipherString = DEFAULT:@SECLEVEL=1

Now when I connect to stunnel, I can verify that I am indeed using ancient crap level security:


New, SSLv3, Cipher is AES256-SHA
Server public key is 1024 bit
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1
    Cipher    : AES256-SHA
    Session-ID: 19D20D30E0026E8417E00402DE939E90770D4658C3A9CFE4DB4E5F2A5454DE9D
    Session-ID-ctx:
    Master-Key: 498C648E77E9B9C944A8B1D16242240A161A05A087881C6AD300718DD9B8C443EA12FB76440B666B7C6634A7E7DBE9D5
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1718352960
    Timeout   : 7200 (sec)
    Verify return code: 10 (certificate has expired)
    Extended master secret: no
---
DONE

I don’t care about the encryption, I could as a matter of fact just run without it, as I only need the reverse proxy aspect of it, to make the AltaVista web server accessible over the LAN/WAN/INTERNET. It’s all fronted with CloudFlare so from the end use POV it’s all encrypted anyways

A rainbow of happiness

Sunshine & rainbows!

Another nice side benefit of this SquashFS setup is that I can forever rebase the disks as the content never changes.


#!/bin/bash
# rebase the disk
rm /usr/local/vm/AltaVista/altavista-c.vmdk
rm /usr/local/vm/AltaVista/altavista-d.vmdk
rm /usr/local/vm/AltaVista/altavista-u.vmdk

qemu-img create -f vmdk -b /usr/local/vmdk/AltaVista_C/altavista-c.vmdk -F vmdk /usr/local/vm/AltaVista/altavista-c.vmdk
qemu-img create -f vmdk -b /usr/local/vmdk/AltaVista_D/altavista-d.vmdk -F vmdk /usr/local/vm/AltaVista/altavista-d.vmdk
qemu-img create -f vmdk -b /usr/local/vmdk/AltaVista_U/altavista-u.vmdk -F vmdk /usr/local/vm/AltaVista/altavista-u.vmdk

qemu-system-i386 -vga std -cpu pentium -m 64 \
        -vnc 192.168.23.1:6 \
        -net none  \
        -hda /usr/local/vm/AltaVista/altavista-c.vmdk \
        -hdb /usr/local/vm/AltaVista/altavista-d.vmdk \
        -hdd /usr/local/vm/AltaVista/altavista-u.vmdk \
        -device pcnet,netdev=alta,mac=5a:00:11:55:22:22  \
        -netdev tap,ifname=tap6,id=alta,script=/usr/local/vm/AltaVista/alta-up,downscript=/usr/local/vm/AltaVista/alta-down

One thing is for sure, it makes hosting AltaVista a bit easier to deal with. And for the sake of archiving, I uploaded a pre-loaded & indexed dataset Altavista Pre-Loaded (squashfs). I found that you can just copy the databases into a new VM, as long as you keep the drive letters the same as your source. So luckily, I had kept the OS on C:, installed AltaVista on D: with all the usenet posts on U:. Even better, for those strapped for space, you don’t technically need the U: drive, if you just want to search. Of course, you probably do want to look at them, but we’ve gone down this road before. And we know where it leads.

Index All the things!

Let’s build a Linux kernel from Windows!

Very exciting

Some of you may remember some 9 years ago, I had put together a package to compile Linux 0.10 under Windows.

Time goes on, and things are lost, and it’d come up somewhere about actually building Linux from Windows, so I thought I’d show it off.

The one thing is that modern machines are just so fast, that it’s almost hard to believe that a 386DX 16 with 4MB of ram would struggle for seemingly hours, what an i7 can churn out in mere seconds.

Time sure flies!

It’s my usual ‘DO IT LIVE’ style, I tried to clean up the audio, but I lost the steps… One day I’ll try to script & build a PowerPoint so it’s more cohesive.

But today is not that day.

Squeezing the bytes out of webhosting & Linux with SquashFS & Overlay

Filesystem      Size  Used Avail Use% Mounted on
/dev/vda1        29G   27G  2.1G  93% /

It’s a problem that we will all face sooner or later in shared environments, running out of disk space. Back in the old days we would just run stacker and be done with it, but what on earth can we do in this modern age?

Well, there is squashfs which is great at creating ultra-compressed read-only filesystems! Well, that is great, but it is READ-ONLY after all, so that is going to suck right? Well thanks to the magic of file system overlays, we can compress our website, and get the much-needed COW (Copy on Write) to another directory giving us the best of both worlds. It’s a common thing in many live CD’s or any seemingly appliance-based OS where you have a hardened read-only OS core that a user cannot delete/infect but gives the appearance of allowing you to update files. Well, that’s all nice but how do you do it manually?

The first thing I did was shut down Apache so I could get a clean compress of my web document root: mksquashfs is pretty easy to use, and in a few minutes of downtime I was able to create a read-only version of my blog’s filesystem. (NOTE that this doesn’t include the database! so anyone wanting to quick & easily archive WordPress, remember there is always more than just the files!).

root@ukweb:/srv/www/blog# mksquashfs . /usr/local/blog.sqshfs
Parallel mksquashfs: Using 1 processor
Creating 4.0 filesystem on /usr/local/blog.sqshfs, block size 131072.
[===================================================================================================-] 67497/67497 100%

Exportable Squashfs 4.0 filesystem, gzip compressed, data block size 131072
        compressed data, compressed metadata, compressed fragments,
        compressed xattrs, compressed ids
        duplicates are removed
Filesystem size 4604333.36 Kbytes (4496.42 Mbytes)
        82.78% of uncompressed filesystem size (5562424.58 Kbytes)
Inode table size 480413 bytes (469.15 Kbytes)
        33.86% of uncompressed inode table size (1418977 bytes)
Directory table size 430607 bytes (420.51 Kbytes)
        32.31% of uncompressed directory table size (1332573 bytes)
Number of duplicate files found 519
Number of inodes 38856
Number of files 32640
Number of fragments 7872
Number of symbolic links 0
Number of device nodes 0
Number of fifo nodes 0
Number of socket nodes 0
Number of directories 6216
Number of ids (unique uids + gids) 2
Number of uids 2
        www-data (33)
        root (0)
Number of gids 2
        www-data (33)
        root (0)

Before compression the blog sat at 5.6GB worth of space. After compressing, it now sits at 4.4GB. Not that awesome, but not that bad either! the blog.sqshfs file can be easily mounted on the command-line like this:

mount -o loop /usr/local/blog.sqshfs /srv/www/blog

And it mounted up just fine, and astonishingly the blog worked. Although it being a read-only filesystem means that I cannot upload new content so all the media would be frozen in time, just as I would no-longer be able to make any updates to the pluggins or the software.

Enter the overlayfs, which lets you specify an ‘upper’ and ‘lower’ level for your filesystem where you can have a read-only lower level, and a read-write upper level. Perfect!

I moved the blog read-only mount to /srv/www/blog-ro created a blog-tmp & blog-rw directories as well and mounted up in overlay mode like this:

mount -t overlay -o lowerdir=/srv/www/blog-ro,upperdir=/srv/www/blog-rw,workdir=/srv/www/blog-tmp overlay /srv/www/blog

You’ll notice that despite all the documentation mentioning overlayfs, along with all the posts, as of Linux 5.15 it’s now called overlay.

root@ukweb:/lib/modules/5.15.0-101-generic/kernel/fs/overlayfs# ls
overlay.ko

At least that was easy enough to find.

But you might say, THATS ALL MANUAL! How on earth are you going to deal with a reboot? rc.local?!

Well, you could but /etc/fstab is much easier!

/usr/local/blog.sqshfs /srv/www/blog-ro squashfs ro,defaults 0 0
overlay /srv/www/blog overlay defaults,lowerdir=/srv/www/blog-ro,upperdir=/srv/www/blog-rw,workdir=/srv/www/blog-tmp 0 2

And just like that, I now have a read-only version of the blog data, in a single easy to backup file, along with writes going to a much more manageable directory for updates.

I guess I should add that for sites that use caching, you’ll want to purge the wp-content/cache directory as it’ll become stale, and there really is no point having a read only version of the chache.

If you can see this, then clearly the site is working!

**UPDATE

So I do have a qemu image piggy-backing on my VPS that runs the Apache on NT 3.1 (superglobalmegacorp.com) site. It’s not very complicated, just NT 3.1 with my terrible apache site. Content doesn’t change, it’s a “just because I can” thing.

So you can happily shut down the VM, and in this case I’m using VMDK’s but it really doesn’t matter, I just like having a more neutral container if I want to move stuff around. Just squash the VMDK by itself into a new squash fs file:

# mksquashfs nt31as.vmdk /usr/local/vmdk/NT31_AdvancedServer.vmdk.squashfs
Parallel mksquashfs: Using 1 processor
Creating 4.0 filesystem on /usr/local/vmdk/NT31_AdvancedServer.vmdk.squashfs, block size 131072.
[=====================================================================================================-] 1390/1390 100%

Exportable Squashfs 4.0 filesystem, gzip compressed, data block size 131072
        compressed data, compressed metadata, compressed fragments,
        compressed xattrs, compressed ids
        duplicates are removed
Filesystem size 72383.38 Kbytes (70.69 Mbytes)
        40.68% of uncompressed filesystem size (177925.66 Kbytes)
Inode table size 3918 bytes (3.83 Kbytes)
        69.64% of uncompressed inode table size (5626 bytes)
Directory table size 31 bytes (0.03 Kbytes)
        93.94% of uncompressed directory table size (33 bytes)
Number of duplicate files found 0
Number of inodes 2
Number of files 1
Number of fragments 0
Number of symbolic links 0
Number of device nodes 0
Number of fifo nodes 0
Number of socket nodes 0
Number of directories 1
Number of ids (unique uids + gids) 1
Number of uids 1
        root (0)
Number of gids 1
        root (0)

The disk image went from 174MB to 71MB. Not bad!

Next, setup a mount point in /etc/fstab

/usr/local/sqshfs/NT31_AdvancedServer.vmdk.squashfs /usr/local/vmdk/NT31_AdvancedServer squashfs ro,defaults 0 0

Now we create the backing file to point to the original VMDK where all write operations will take place. And of course this means that the site can be reverted very quickly if something goes wrong.

qemu-img create -f vmdk -b /usr/local/vmdk/NT31_AdvancedServer/nt31as.vmdk -F vmdk nt31as.vmdk
Windows NT 3.1 with compressed backing store VMDK

And just like that, we’ve now up and running!

Building MS-DOS 4.00 under OS/2 2.x

Building & Booting DOS on OS/2!

Now that we’ve moved beyond the initial shockwave of the MS-DOS 4.00 source code dump, I thought it was time to try to pull off the ultimate trick of the time, building under OS/2 and using the exciting feature of the time “DOS from Drive A:” Long before VMware / Virtual PC for the PC OS/2 took Intel’s 80386’s hardware virtualization mode, “v86 mode” to the logical conclusion allowing you to boot native MS-DOS under OS/2. Sadly, the old 1989-1991 OS/2 betas do not include this feature. Although I have to wonder if it did exist and just wasn’t publicly available.

Many of the programs used to build MS-DOS are off the shelf, the MASM assembler, Microsoft C 5.1, and its associated tools are just retail versions. To change things up, I did use the 386MASM assembler just to see if it maintained MASM 5.1 compatibility. And it does. The only gotcha is that all the tools are *NOT* marked Presentation Manager compatible, so launching them from a window opens a full screen session. Very annoying!

exehdr

I’m guessing the fix is in a toolkit? Either way, in Microsoft C 6.0, the utility exehdr lets us modify an OS/2 executable so it’ll now be WINDOWCOMPAT. So at least it ‘feels’ better now.

One thing is for sure, building DOS under OS/2 is a lot more enjoyable than doing a native build as you can minimize the build task, although the MS-DOS only programs do pop up when it generates text indexes & tables. But you do retain some control of your machine during the build, which is great! Although E is a terrible editor for source code, and the one in 6.78 has a nasty bug where it’ll truncate large files. Were people really using text mode editors for everything back then? I guess i like the fonts of the GUI, despite having used machines of the era.

Otherwise, the end result is the same, you get a build of DOS 4.

I went ahead and tried to build using 6.78 and no doubt compiling DOS is an absolute torture test. So far, the DOS Box has locked OS/2 once, and PM Shell has crashed once as well.

I altered the Makefiles to use ‘rm’ instead of the built in ‘del’ command, because if you try to delete a file that doesn’t exist, del returns an error, which then triggers an end to the NMAKE process. Very annoying! However, the ‘rm’ included in Microsoft C 5.1 doesn’t suffer the same defect. Using 86Box with an 83Mhz Pentium OverDrive it took about 18 minutes to build DOS-4.

Building DOS 4 on OS/2 6.78

I did capture the video and converted it to a GIF so you can quickly see the reboot & the UI crashing. FUN!

Compiled under OS/2

And it even boots!

For anyone interested I’ve put zips on archive.org that can be extracted under OS/2. I also made a pkzip disk set incase loading a 6MB zip file is an issue.

Building MS-DOS 4.00 under OS/2 2.x : neozeede : Free Download, Borrow, and Streaming : Internet Archive

DooM, GCC & AI

One of the things that always annoyed me about DooM is the fixed point math. It relies on a 64bit data type, which many 32bit platform just lack. Namely the FixedMul & FixedDiv.

fixed_t FixedMul
( fixed_t a,
fixed_t b )
{
return ((long long) a * (long long) b) >> FRACBITS;
}

They are generally re-written into assembly, at least for the i386 getting around the whole 64bit on a 32bit platform.

FixedMul:	
	pushl %ebp
	movl %esp,%ebp
	movl 8(%ebp),%eax
	imull 12(%ebp)
	shrdl $16,%edx,%eax
	popl %ebp
	ret

FixedDiv2:
	pushl %ebp
	movl %esp,%ebp
	movl 8(%ebp),%eax
	cdq
	shldl $16,%eax,%edx
	sall	$16,%eax
	idivl	12(%ebp)
	popl %ebp
	ret

So that’d always been the ‘catch’ when porting Doom is that you either need a ‘long long’ data type, or the custom assembly or you basically are out of luck.

I know I’m a weird person, but I do like going backwards in terms of software, while most people want latest GCC 14 targeting old machines or some other hack, I prefer the opposite, trying to get the oldest stuff running on something new(er). In this case, it’s GCC 1.27.

While much of the old GCC history is lost, I did my best to collect as many versions as I could find here, along with doing patches in reverse to ‘reconstruct’ many old versions. The results are on archive.org. And what is significant from this, is the first version of GCC with i386 support appears in version 1.27.

From the internals-1 file we can find out that we all have William Schelter to thank for doing the bulk of the 386 port of GCC.

William Schelter did most of the work on the Intel 80386 support.

Internals-1 – gcc 1.27

With the first commit being on May 29th, 1988:

Sun May 29 00:20:23 1988 Richard Stallman (rms at sugar-bombs.ai.mit.edu)
...
* tm-att386.h: New file.

GCC 1.25

The first GCC with i386 parts is 1.25, however it tends to emit the instruction movsbl, which GAS doesn’t like. Comparing the output to GCC 1.40 reveals this:

-	movsbl -12(%ebp),%ax
+	movsbw -12(%ebp),%ax

It’s trivial enough to change to a movsbw, but there are some other issues going on, and even the Infocom ’87 interpreter won’t fully build & run. The files input.c & print.c have to be built with a later version of GCC, in this case I used GCC 1.40.

8&% compiled with GCC 1.25!

However when using the old XenixNT build thing I did, I do get a runnable EXE!

GCC 1.25 targeting DJGPP v1

I added the BSD targeting files from 1.27 allowing it to generate the needed underscores in the right places, as 1.25 by default only supports AT&T syntax. I guess the best way to illustrate it is to compile the compiler twice, once as the AT&T compiler, and the next being the BSD compiler, and compare their output:

cc1-att.exe hi.cpp -quiet -dumpbase hi.c -version -o hi-att.s
GNU C version 1.25 (80386, ATT syntax) compiled by GNU C version 4.8.1.

.text
.LC0:
        .byte 0x31,0x2e,0x32,0x35,0x0
.LC1:
        .byte 0x68,0x65,0x6c,0x6c,0x6f,0x20,0x66,0x72,0x6f,0x6d
        .byte 0x20,0x25,0x73,0xa,0x0
        .align 2
.globl main
main:
        pushl %ebp
        movl %esp,%ebp
        pushl $.LC0
        pushl $.LC1
        call printf
.L1:
        leave
        ret

And then looking at the BSD syntax:

cc1-bsd.exe hi.cpp -quiet -dumpbase hi.c -version -o hi-bsd.s
GNU C version 1.25 (80386, BSD syntax) compiled by GNU C version 4.8.1.

        .file   "hi.c"
.text
LC0:
        .byte 0x31,0x2e,0x32,0x35,0x0
LC1:
        .byte 0x68,0x65,0x6c,0x6c,0x6f,0x20,0x66,0x72,0x6f,0x6d
        .byte 0x20,0x25,0x73,0xa,0x0
        .align 1
.globl _main
_main:
        pushl %ebp
        movl %esp,%ebp
        pushl $LC0
        pushl $LC1
        call _printf
L1:
        leave
        ret

As you can see main: becomes _main:, just as labels (LC0/LC1) have a prepended, while in BSD they do not. There are no doubt countless other nuanced differences, but for the assembler & operating system to match you want these to align. Thankfully calling conventions are mostly the same per processor so you can add the underscores to the AT&T target and get something that’ll run, not only on DJGPP but also Win32, as MinGW32 uses BSD syntax at its heart!

C:\xdjgpp.v1\src>gcc hi-bsd.s -o hi.exe

C:\xdjgpp.v1\src>wsl file hi.exe
hi.exe: PE32 executable (console) Intel 80386, for MS Windows

C:\xdjgpp.v1\src>hi
hello from 1.25

Not that we really need to go all the way and have GCC 1.25 running on anything much, although at the same time it’s kind of fun!

Reaching out for help

The oldest & most robust GCC is 1.27, and I’d been able to use that to build DooM before, but the caveat is of course the fixed point math. I’d asked smarter people than I years ago about this problem, and basically was told to figure it out for myself. After all its ‘trivial’. But alas, I’m not smart. What I would do is build the fixed point math with GCC and try to re-work that into other compilers, although again for platforms without GCC or the target CPU lacking the 64bit data type is well.. fatal.

But AI, sadly for it, is compelled to help. So I just went ahead and asked and got a surprising result!

Sydney strikes back!

It’s very C++ like but it’s trivial enough to make it into old C.

Sydney’s fixed-point guess

Well on the one hand it does actually load up and play. But the controls go wild and I’m pulled into the intersection of these boxes, and unable to move. And as I rotate the floor and walls clip in and out. It’s very weird.

Not knowing anything about anything, I saw this ‘guard’ on the fixed division and tried to add that to the multiply:

	if ( (abs(a)>>14) >= abs(b))
		return (a^b)<0 ? MININT : MAXINT;

And I got something even weirder!

Now with absolute guards!

Not only that but the engine crashes! Not good.

After thinking about it on and off, asking for more help and going nowhere, I just gave up. It’s something beyond my skill, and apparently the AI as well. Until I had one of those moments in a dream where I had somehow told myself I bet the integers are not unsigned, and obviously fixed-point math needs all the bits, and it’s such a trivial fix, that even I should have figured it out.

I woke up at 4am and fired up the computer to see if it did anything. I was surprised to see that yes, in fact the integers were signed. I added the one key word, and recompiled using GCC 2.2:

Now with unsigned integers

And it RAN! I tried GCC 1.39, and too ran! I then made sure there was no assembly modules being called accidentally, and then re-built with GCC 1.27, and yeah, it runs!

Armed with a simple port of DooM to Win32, I went ahead and put in the fixed-point solution, and used Visual C++ 1.10 aka Microsoft C/C++ 8.0 to build DooM, and yes it works there too!

In the end I guarded it around a long long type, as I’m sure it’s much more faster, but for those without the types or any assembly skill, here is the solution:

/* Fixme. __USE_C_FIXED__ or something. */
fixed_t
FixedMul
        ( fixed_t a,
        fixed_t b )
{
#ifdef HAVE_LONG_LONG
    return ((long long) a * (long long) b) >> FRACBITS;
#else
    unsigned int ah,al,bh,bl,result;

    ah = (a >> FRACBITS);
    al = (a & (FRACUNIT-1));
    bh = (b >> FRACBITS);
    bl = (b & (FRACUNIT-1));

    /* Multiply the parts separately    */
    result = (ah * bh) << FRACBITS;     /* High*High    */
    result += ah * bl;                  /* High*Low     */
    result += al * bh;                  /* Low*High     */
    /* Low*Low part doesn't need to be calculated because it doesn't contribute to the result after shifting

    // Shift right by FRACBITS to get the fixed-point result                                            */
    result += (al * bl) >> FRACBITS;

    return (fixed_t)result;
#endif
}

/* */
/* FixedDiv, C version. */
/* */
fixed_t
FixedDiv2
        ( fixed_t a,
        fixed_t b )
{
#ifdef HAVE_LONG_LONG
        long long c;
        c = ((long long)a<<16) / ((long long)b);
        return (fixed_t) c;
#else
        double c;

        c = ((double)a) / ((double)b) * FRACUNIT;

        if (c >= 2147483648.0 || c < -2147483648.0)
                I_Error("FixedDiv: divide by zero");
        return (fixed_t) c;
#endif
}

fixed_t
FixedDiv
        ( fixed_t a,
        fixed_t b )
{
        if ( (abs(a)>>14) >= abs(b))
                return (a^b)<0 ? MININT : MAXINT;
        return FixedDiv2 (a,b);
}

I haven’t tested it on Big Endian machines yet. I’ve updated my terrible DooM engine port, along with Doom-New for DOS. Additionally, I’ve been able to confirm it works with Watcom 9-OpenWatcom 2. It might even work with 7 & 8 but I haven’t tried.

In Defense of the Mac Pro 2023

guest post by neozeed‘s nephew

There are a few reasons to get an M2 Mac Pro and although many will say the Studio is a better buy for value: that’s only true if you’re not after these important considerations:

  • The ability to install your own *bootable* SSD: nearly every major Mac reviewer ignored this insanely important feature.
  • The ability to install internal storage (and go beyond 8 TB), period: do we really want a cocktail of external HDDs attached? I don’t!
  • The ability to install an internal USB A licensing dongle: unless you’re sharing your dongle over the network with 3rd party software from an RPi hiding in a closet (you should try VirtualHere if you want cross-platform dongle sharing it’s great), you don’t want to accidentally shear it off costing thousands of dollars of lost licensing.
  • The Magic Keyboard and (black) Magic Mouse are bundled (this is not the case with the Mac Studio or the MacBook Pro adding a substanstial cost. However, since the AppleCare+ is more expensive for the Mac Pro over the Mac Studio you could argue these costs cancel themselves out… unless you’re Icarus with a wax wallet instead of wax wings and never purchase AppleCare+).

Recently ‘GoFetch’ made the headlines, but it’s irrelevant for a variety of reasons in my opinion: 1) you won’t have WAN-exploitable instances of GoFetch in the real world, 2) it does indeed affect some Intel processors and probably others. The way all processors are designed now with speculative execution, CVE-after-CVE is unavoidable so the sensationalization has worn out its appeal. Even the once-ironclad AMD processors are afflicted with a bunch of nasty CVEs now too. \rant

Mac Pro vs PS/2 Model 95

After an eye-watering $8000: refurbished base model with AppleCare+ 🤮💸💸, we’re greeted with our new friend. The Cheese Grater (2023 Mac Pro) has befriended the Ardent Tool of Capitalism (PS/2 Model 95)! It’s odd how both share silly nicknames and a very similar height sans handles. Both systems symbolize the same sentiment that Louis Ohland shared many years ago: “Think of a business computer being used for purely personal reasons. Fist pump at the man! Isn’t using a corporate tool because you can an expression of free will?”*

*Louis Ohland is the guy who nicknamed the PS/2 Model 95, the Ardent Tool of Capitalism.

Q&A

Q: will I grate cheese on both of them?

A: only if you clean up the cheese residue for me. Are Personal System/2s even food-safe???

Storage

Sonnet M.2 4×4 NVMe PCI-e

The first thing we’ll need to do is install an NVMe PCI-e card. I’m going with the overly-priced “Sonnet M.2 4×4”, because the 2×4 card is nearly the same price making it a horribly valued product and we may as well expand this thing with four NVMes to get our money’s worth. It’s not really clear if the Sonnet M.2 4×4’s controller outperforms the Sonnet M.2 2×4 (they don’t use the same one), but both operate on gen 3 and the NVMes themselves are gen 3 so none of it really matters. There are much cheaper NVMe PCI-e cards but most are not compatible with Macs, you’re paying the tax for the fancy firmware… otherwise buy a much cheaper card if you’re on Windows or Linux. The card only came in a pink ‘static suppressant bag’ instead of a true antistatic bag which is laughable at how much sonnet is charging, and Amazon appears to have taken a bite out of the box.

For the primary boot NVMe we’re going with a 2TB 970 EVO Plus. I know Louis Rossmann decried them as being unreliable after he torched a bunch in some custom gaming rigs with sketchy PSUs, but they’re good drives if you don’t kill them with dirty PSU voltage rails. Always use quality PSUs folks. This is why many Maxtors failed due to the ST SMOOTH chips receiving power from PSUs outputting higher than 12v, and not the drives themselves… same thing applies today when you eclipse 12v on your power rails. I’ve also been running one in a ThinkPad for more than a year and it’s been fine.

For the remaining tertiary storage we’re going with some WD Green SN350s: solely because they’re compatible with macOS — the macOS compatibility with NVMes is very specific unfortunately. Otherwise I would have went with more TeamGroup 4TB drives as they’re one of the best value for money (particularly the TM8FP4004T0C101, it uses better NANDs than the more expensive and inferior 4TB offerings from Crucial and WD). Yeah… the cost of NVMe disks isn’t absolute, sometimes cheaper ones use better NANDs and you can be fleeced by brand recognition and false-positive specs on gen4 which I imagine is what Crucial capitalizes on.

[If you don’t know what I’m talking about: the Crucial and Western Digital NVMe drives always cheap out and use QLC NANDs instead of proper TLC NANDs as TeamGroup and Samsung do; and obviously they’re not going to advertise they’re cheating you and will price their products the same as the competition. Very similar to the whole SMR/CMR debacle, why would Western Digital tell you you’re buying something cheaper at a premium cost??? Caching is an entirely different thing separate to this and usually only the Samsung drives have ‘true’ dedicated cache logic, which is why I’m using the 970 EVO Plus as a boot/OS NVMe]

reinstalling MacOS

Fortunately we don’t need a second mac to perform OS reinstallation so the ‘Apple Configurator’ is not needed. The procedure is as simple as this: Press & hold power button until the recovery menu pops up, choose ‘continue’, choose reinstall OS, choose the new drive (in this case the Samsung drive I just formatted as “OS”). I know a lot of people raise an eyebrow requiring a second mac for when the system does actually need to be completely restored if it can’t boot into the internal recovery mode; just when you haven’t paid Apple enough you also need a second Mac to perform recovery and restoration. Even neozeed himself encountered this problem and with a heavy sigh (a very heavy sigh) and mild disbelief, set up a macOS VM for restoration since he only owns one. 😂

Once this is completed we’ll no longer be using the proprietary SSD that’s present on the Mac Pro. It DOES still need to be present in the system for the computer to POST (Apple marries it against the security IC so it’s intrinsic and serialized to the computer based on configured storage), but presumably as it won’t be written to anymore it’ll never become exhausted from write cycles… and even if it did fail over time, as a result of ordering the bottom-of-the-barrel 1TB model I could just buy another ‘cheap’ 1TB card which would allow the system to resume POSTing once again. If the soldered-in RAM or CPU fails then it’s game over; as much micro-soldering as I do, I refuse to purchase even more tools to swap out underfilled BGA ICs… and then of course you have to hope employees at Foxconn actually managed to sneak out unused genuine ones to be resold on AliExpress or eBay. *sigh*

With us now being able to use our own bootable SSD, the primary failure and annoyance of ARM-based Macs is now mitigated. For the Mac Studio you could buy backup replacement SSDs to constantly replace as they wear out (they would have to match what storage size the system was preconfigured with), but keep in mind I can add 8TB cheaply and have my own bootable SSD. And in the event you need to do data recovery or read the drive on another system, anything — even your grandma’s phonograph — can read NVMes so it’s much less of a hassle. As much as I hate to say it I think the Mac Studio makes less sense over the Mac Pro BECAUSE of the storage… you’re already buying an overpriced computer, may as well go the full distance for proper storage? Everyone’s living in the honeymoon phase right now while all of the NANDs are under warranty and still functioning… but once they start failing it’ll be a nasty money pit at best, or unfixable at worst. And do you know how many people make one computer their whole life and allow it to spontaneously fail with no backups?

ARE YOU NOT ENTERTAINED?

An ARM-based Mac using internal NVMes, is that not a nice thing? ARE YOU NOT ENTERTAINED? And no need to pay ~$2000 for 8TB. I did have to shell out $400 for the stupid SoNNeT card and $400 for the SSDs… buuut if I paid $2000 worth of SSDs I would far eclipse 8TB. In this screenshot you can also see the ‘OS’ Samsung SSD now the primary ‘Startup disk’. Fortunately, Apple’s utility automatically switched it over after I reinstalled the OS to this drive shockingly enough, so nothing more needed even on that.

Internal USB, perfect for Dongles:

Installing the iLok dongle

The iLok licensing dongle installs nicely inside the internal USB A port. Kind of reminds me of those internal VMware USB A ports meant for the ESX installation… and then you know they’d eventually go bad or corrupt themselves and the internal IT of that company never makes a backup so then you need to reconfigure ESX from scratch… good times. What? I’m not salty, not salty at all. The Sonnet NVMe card being installed on the first slot (bottom) does seem to bring more attention to the fact there’s so many unpopulated PCI-e slots.

What should be used as the display option?

1. The Dell UltraSharp U3224KB 6K actually has a few potential compatibility problems with macOS or the hardware (it’s not really well-known as Dell support gave up troubleshooting it), so you’ll get various screen distortions. It’s also possibly one of the most UGLY products I’ve ever seen in my life… the web camera looks like a malignancy, and I absolutely can’t stand silver-painted plastic. Complain about Apple’s prices all you want, at least they use nice materials.

2. The Pro Display XDR is just a little bit too much for my taste and sometimes temperamental as it’s such a complicated display (contrary to popular mythology it does not use OLED technology so it shouldn’t burn out over time). I honestly don’t think I would encounter any problems if I bought a Pro Display XDR but the cost is too much.

It’s Free Real Estate – Tim & Eric

3. That basically leaves us with the Studio Display. A lot of the 3rd party Samsung/ASUS/LG 4K or 5K offerings have dramatically inferior colour or a larger pixel size… and there’s still the potential aspect of compatibility since non-Apple hardware sometimes doesn’t play nicely. While the Studio Display is much-maligned with its high cost and strangely attached power plug, its DPI is the same as the Pro Display XDR you just get less screen real-estate and inferior contrast which I don’t care too much about. It will still look much better than your garden variety LG 27” 4K UHD Ultrafine because the colour is calibrated very well and it gets decently bright… again… I wish YouTube reviewers would point some of these things out instead assume that every display is equivalent to Apple’s offerings when they’re not. And in the event, you do find the 5K 27″ displays from other manufacturers they’re still at 60Hz. The refurbished Studio Display I had my eye on from Apple is no longer available, so I’ll be waiting for a bit until they stock another one… or maybe they’ll get a heavily marked down Pro Display XDR…. in the meantime, I’m stuck using one of my gaming monitors which has 240Hz and strobing to reduce ghosting, which does work on macOS!.. and makes macOS look so different since I’m used to how it looks with all of the ghosting all the time.

Another little something that’s rarely discussed: the nano-texture glass option causes a slight ‘frosting’ which is especially noticeable on text… it’s only meant as a compromise if you’re working in a literal sun room, sometimes more expensive does not mean better. This is exemplified with the M2 MacBook Air situation: if you opted for the superior GPU it ended up running more slowly because of the thermal throttling so the lower-end GPU option is more performant, lol. Of course Apple doesn’t always disclose these caveats or finer details, but their divisions responsible for publishing the products may not be privy to them.

Peripherals:

Onto the peripherals: I will indeed be using the Magic Mouse… before your jaw drops and you grab some tomatoes while calling me a heretic, let me explain. The Magic Mouse is one of the few peripherals with velocity sensitive 360º scrolling AND fully integrated in the UI of the operating system. This is extraordinarily similar and analogous to IBM’s ScrollPoint which also offered dynamic 360º scrolling and to a lesser extent the TrackPoint scrolling but which only offers vertical and horizontal. Needless to say 360º scrolling and horizontal scrolling is something I use all the time and cannot fathom why we still even have (notched!) mouse wheels. It’s bizarrely a mouse Apple seemingly designed specifically for me and nobody else, I imagine average or larger hands would be extremely uncomfortable with it and Apple really should offer a larger version to encompass a better demographic.

Men & Mice

The Magic Mouse and ScrollPoint Pro share very similar design philosophies in the way we scroll. I also made another strange discovery when I was looking for some more flat slick mousepads since the Magic Mice don’t work well on cloth ones at all, and that are these 3M ‘Precise’ mouse pads: AMAZON LINK.

Apparently the 3M mouse pads have a reflective material which allows the lasers to use less strength and thus supposedly saves 50% battery life, some Magic Mouse users affirmed this, so we’ll see how this goes down. It’s kind of surprising I’ve never heard of any tech reviewers mention these because saving 50% of battery life on a wireless mouse is huge.

Keyboards..

There’s a lot of good reasons to NOT use Bluetooth keyboards due to wireless keylogging, there’s not going to be anyone with that talent in rural Canada so I’m in the clear. You could buy a Matias keyboard but they’re actually worse in many aspects than the 1st party Apple keyboards: the legend printing is of dramatically worse quality, the surface of the keycaps don’t have that special velvety texture, and the snappiness of the scissor switches is probably worse. While I have many mechanical keyboards, I don’t care so much about it anymore. The Apple Magic Keyboard is just a little bit too flat for my tastes today so I ordered a “ESC Flip PRO Computer Keyboard Stand”, which can stick on the back and give you different height adjustments if needed.

onboard LEDs everywhere.

Both the iLok and Sonnet NVMe card have so many LEDs on them you can see the lightshow through the rear of the ‘grater’ now.

Now my plans are to use this thing for at least a decade to get my money’s worth: will 64GB of RAM be enough? To that I say: 64GB ought to be enough for anybody. The only major hindrance will be the forced software obsolescence when the Apple overlords declare it will not be receiving anymore updates… and then you know things like the Roland Cloud and other major vendor software will cease to get updates and functionally work. It’s appalling at how all software is heavily DRMed and requires a live account to work against. At the very least when WWIII breaks out I’ll have plenty of premium aluminum to donate to the state, forged by Tim Apple himself!

For the record I was never really an ‘Apple person’, but they’ve finally fixed all of the problems (mice have two buttons and the keyboard layout is restored to be more IBM-like) and made a product that fulfills everything I’ve ever wanted… AND forced developers to program for ARM: so now my Stallman-not-approved-absolutely-proprietary audio software runs incredibly well on a non-x86 platform. Astounding. Yeah there were some 3rd party mice that had two buttons for Macs ‘back in the day’ but a good portion of the *software* and games weren’t programmed for a real right click rendering it useless. I remember watching a ‘making-of’ video of the Myst developers pushing down Ctrl with the mouse to right click EVERY SINGLE TIME in their 3D modelling software and nearly fell off my chair… it’s quite jarring when you need to press a button on the keyboard at the same time with clicking the mouse so I’ve no idea how they tolerated that. Maybe they loved doing it? Who knows.

It’s crazy how much changes, and how much is the same

So everyone is going nuts for free VMware Workstation

I haven’t had a moment to really look into it, but Mathew Duggan‘s take on the whole experience: The Worst Website In The Entire World pretty much sums it up the whole thing.

On the plus side this makes things like adding VMnetworks and configuring them all possible for lowly end user people like me, and makes stuff like SNA networking a bit more easier.

But what is the catch?

There is always a catch!

I have a feeling this is just like when Java became ‘free’. And then followed the audits and lawsuits. Most of this legal strong arming is all under NDAs so don’t expect to find much but ask anyone who’d used Oracle, and balked at some terms, and found themselves under a JDK download audit.

The free version is available for non-commercial, personal and home use. We also encourage students and non-profit organizations to benefit from this offering.

Commercial organizations require commercial licenses to use Workstation Player.

And there is the trap.

Download at home, and away from work.

You’ve been warned.

Compiling MS-DOS 4.0 from DOS 4.0, on a PS/2!

have patience. It does work. Even booting from the SPOCK SCSI CARD which all the other DOS4 images all failed.

The best way for a native build is the zip in the releases.

Release Now can boot from hard disk! · neozeed/dos400 (github.com)

With a 16Mhz 80386 it took 70 minutes. I just formatted a blank image on the gotek, copied IO.SYS, MSDOS.SYS and COMMAND.COM, then rebooted. went back to the compiled DOS 4, and re-formatted the floppy as a system disk so the attributes are set. (DOS 5 lets you change system files), and yeah. It can be done!

Let me spell out the steps, in this case I’m going to use Windows 10. I use the git from the WSL (Windows subsystem for Linux) I have DOSBox mount c:\dos as my c: drive . ZIP/UNZIP are Info-ZIP versions, you MUST have the Win32 native version!

- md \dos
- md \dos\temp
- wsl git clone https://github.com/microsoft/MS-DOS
- cd MS-DOS\v4.0
- zip -r \dos\temp\src.zip src\*.*
- cd \dos
- unzip -a -LL temp\src.zip
- start dosbox
- cd \src
- edit setenv.bat to reflect the paths:
  set BAKROOT=c:
  set LIB=%BAKROOT%\src\tools\bld\lib
  set INCLUDE=%BAKROOT%\src\tools\bld\inc
  set PATH=%PATH%;%BAKROOT%\src\tools
- setenv
- nmake
it will then fail in mapper on getmsg.asm change the 3 chars to a '-'
- nmake
- cd ..
- nmake

It will then fail building select

- edit select2.asm
- edit usa.inf
- nmake
- cd ..
- nmake

and now it’ll be done compiling.

continuing from dosbox, you need a 1.44mb fat formatted disk image somedos144.img . I used a dos 6.22 diskette, it needs the bootsector already in place to load io.sys/msdos.sys

- cd \src
- md bin
- cpy bin
- imgmount a somedos144.img -t floppy
- a:
- del *.*
- copy c:\src\bin\io.sys
- copy c:\src\bin\msdos.sys
- copy c:\src\bin\http://command.com
- boot -l a:

And now I’ve booted MS-DOS 4.00 from within DOBOX!

Also as interest to most people there is a bug in msload.asm, where DOS 4.0 won’t boot on a lot of machines, from VMware, Qemu and even my PS/2. It’s a small fix to the IO.SYS initial stack being too small. Props to Michal Necasek for the fix!

For further guidance here is a video spelling it all out: