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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for March 2nd, 2022

MemTest86 for MBR booting systems: use the really old version 4.3

Posted by jpluimers on 2022/03/02

Sometimes you come across old systems that do not support UEFI booting, so for memory testing you need tools that either are embedded on something like a Linux image that os in MBR, or the plain ISO download of older versions.

I opted for the latest “older” version 4.3 of MemTest86 [Wayback]:

As MemTest86 V9 supports only the newer UEFI platform, older PCs without UEFI support would be unable to boot MemTest86. In order to run MemTest86, PCs with legacy BIOS platform must use the older V4 release of MemTest86. The download links for the V4 downloads are still provided for those that prefer to work with the V4 bootable images.

V4 Windows Downloads: Download
Image for creating bootable CD [Wayback] Download
Image for creating bootable USB Drive [Wayback] Download
Image for creating bootable Floppy Drive [Wayback] Download
V4 Linux/Mac Downloads: Download
Image for creating bootable CD [Wayback] Download
Image for creating bootable USB Drive [Wayback] Download
Image for creating bootable Floppy Drive [Wayback] Download


Posted in DELL-9200, Hardware, HP XW6600, Memory, Power User | Leave a Comment »

Windows applications: storing your data in the correct place (Roaming, Local, LocalLow, not Documents)

Posted by jpluimers on 2022/03/02

This is a follow on the below TomTom HOME complaint: Know where your application should store its data.

I know this can be tough, especially for applications that were developed before Windows Vista came around: that’s when CSIDL were introduced. But still: Windows XP already had %APPDATA% (the environment variable equivalent to CSIDL_APPDATA, it pointed to %USERPROFILE%\\Application Data)

Applications should store data under either of below locations. Values are KNOWNFOLDERID constants with CSIDL constants in parenthesis where available. Some have .NET equivalents in the System.Environment.SpecialFolder enumeration:


    The file system directory that serves as a data repository for local (nonroaming) applications.

  • FOLDERID_LocalAppDataLow (n/a)

    The file system directory that serves as a data repository for local (nonroaming) applications that run under “low integrity” (like in a web browser).


     The file system directory that serves as a common repository for application-specific data.

Do not use FOLDERID_Documents (CSIDL_MYDOCUMENTS) as this is specific to user documents, not application data.

The virtual folder that represents the My Documents desktop item. This value is equivalent to CSIDL_PERSONAL.

Basically use FOLDERID_LocalAppData for data that is machine specific and FOLDERID_RoamingAppData for data that should travel to other machines when the user logs on to them.

Be very careful how much you store as potentially roamed data as these can go over slow networks (both low bandwidth and low latency).


Read the rest of this entry »

Posted in .NET, Development, Software Development, Windows Development | Leave a Comment »

Too bad: ESXi busybox has `diff`, but not `patch`

Posted by jpluimers on 2022/03/02

On my ESXi boxes, I have a directory with local scripts that in part depend on the machine.

So I contemplated patching the dending parts with patch.

Then I found out that the BusyBox that VMware built for ESXi does have diff, but not patch:

# $(readlink -f "`which diff`")
BusyBox v1.29.3 (2021-01-17 01:25:00 PST) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
copyright notices.

Usage: busybox [function [arguments]...]
   or: busybox --list
   or: function [arguments]...

    BusyBox is a multi-call binary that combines many common Unix
    utilities into a single executable.  Most people will create a
    link to busybox for each function they wish to use and BusyBox
    will act like whatever it was invoked as.

Currently defined functions:
    addgroup, adduser, arch, ash, awk, basename, bunzip2, bzcat, bzip2, cat, chgrp, chmod, chown, chvt, cksum, clear, cp, crond,
    cut, date, dd, delgroup, deluser, diff, dirname, dnsdomainname, du, echo, egrep, eject, env, expr, false, fdisk, fgrep, find,
    fstrim, getty, grep, groups, gunzip, gzip, halt, head, hexdump, hostname, inetd, init, kill, ln, logger, login, ls, lzop,
    lzopcat, md5sum, mkdir, mkfifo, mknod, mktemp, more, mv, nohup, nslookup, od, passwd, poweroff, printf, readlink, reboot,
    reset, resize, rm, rmdir, sed, seq, setsid, sh, sha1sum, sha256sum, sha3sum, sha512sum, sleep, sort, ssl_client, stat, stty,
    sum, sync, tail, tar, taskset, tee, test, time, timeout, touch, true, uname, uniq, unlink, unlzop, unzip, usleep, vi, watch,
    wc, wget, which, who, xargs, zcat

This list is much shorter than the applets that are supported in [Wayback] BusyBox – The Swiss Army Knife of Embedded Linux, so VMware did cut out quite a few.

Generating the above output

The command-line trick above first expands diff using the output of which diff, then finds out where it links to through the readlink -f wrapper there the back-quotes “`” get this output:

# readlink -f "`which diff`"

Finally the $(...) executes the output of readlink.

It is based on [Wayback] bash – How to resolve symbolic links in a shell script – Stack Overflow

readlink -f "$path"

Editor’s note: The above works with GNU readlink and FreeBSD/PC-BSD/OpenBSD readlink, but not on OS X as of 10.11.GNU readlink offers additional, related options…

Need to devise a way to apply patches

Given there is no patch, I need to think about a good way to apply patches, for instance to snip this into /etc/rc.local.d/ in a reliable way:


# local binaries are in /vmfs/volumes/NVMe980PRO_1TB/local-bin/
# link that directory from /opt/bin
# then add /opt/bin to the PATH in /etc/profile so that on each logon it becomes available
# this means you need to logon twice after reboot:
# - first to patch /etc/profile
# - second to have the correct PATH loaded from /etc/profile
# direcory exist trick from

patch_etc_profile_PATH() {
    if [ -d "$1" ]; then
      ln -s "$1" "/opt/bin"
      sed -i -e 's!PATH=/bin:/sbin!PATH=/bin:/sbin:/opt/bin/!' /etc/profile

patch_etc_profile_PATH /vmfs/volumes/NVMe980PRO_1TB/local-bin/



Posted in *nix, *nix-tools, ash/dash, ash/dash development, BusyBox, Development, ESXi6, ESXi6.5, ESXi6.7, ESXi7, Power User, Scripting, Software Development, Virtualization, VMware, VMware ESXi | Leave a Comment »

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