Archive for the 'Services' Category

Linux on macOS w/ Xhyve & Hypervisor.framework

Saturday, December 8th, 2018

Just the usual quite note for myself ;-)

xhyve -A -m 512m -c2 -f kexec,~/Downloads/boot64/vmlinuz_4.19.4-dist,initrd2,”earlyprintk=serial console=ttyS0 root=/dev/vda1″ -s 0:0,hostbridge -s 31,lpc -l com1,stdio -s 2,virtio-blk,~/Downloads/linux-vm.img -s 4:0,virtio-net -s 5,fbuf,tcp=127.0.0.1:29000,w=1024,h=768

Apache redirect except well known acme challenge?

Sunday, October 7th, 2018

Sure, here we go:

RedirectMatch 301 ^(?!/\.well-known/acme-challenge/).* https://example.com$0

Secret vintage Windows setup.exe options

Saturday, September 8th, 2018

So when you install some outdated, unsupported and vintage Windows, e.g. 95, for some retro fun or reverse engineering (of old VGA acceleration) the setup.exe was hanging for me in pcem scanning the (emulated) system for problems and such. Turns out the setup.exe has quite some option to skip things, … like:

/IS do not run ScanDisk
/IM skip the memory check
/ID skip the disk-space check
/iw skip Microsoft EULA licensing dialogs

20 years, and over 400 scanner drivers

Friday, August 24th, 2018

Quite exactly 20 years ago I purchased my first scanner, after saving for years for my first computer: A Pentium 120, at first even running with our old ISA VGA card from my farther’s ageing 386sx25. Lafter, after saving more for my first VGA card, an ELSA Victory 3D w/ S3/Virge3D, it was also time for the first peripherals and of course to get analog material into the digital world I needed a scanner: a c’t mgazine well rated AVision AV630CS. But as Windows crashed too often than not on me, it was also time to migrate to Linux. Remember that was 1998 when few actually heard about it. And of course I had to write my own SANE scanner driver - and the rest is history:

ExactScan.com.

[self note:@”gdb”];

Saturday, August 11th, 2018

set solib-search-path ./lib64
# or: set solib-absolute-prefix ./lib64
file usr/bin/something
core-file core

AT command notes

Thursday, March 15th, 2018

so it is that time of the decade again, that you need to poke with some AT modem commands, e.g. for 3G / LTE networks, …

Does the SIM card need a PIN?
at+cpin?

Enter the PIN if required:
AT+CPIN=1234

Current network:
AT+COPS?

Update: special service numbers, e.g. balance:
AT+CUSD=1,”*100#”

remapping bad spinning disk storage blocks

Monday, December 18th, 2017

Your good, old-fashioned rotating hard disk storage starts to develop bad sectors?

Dec 17 10:49:47 server kernel: end_request: I/O error, dev sdb, sector 300037184

One of the most easiest, quick and dirty ways to remap them on Linux (e.g. easier than fumbling with dd if= of=)?

Double check:

hdparm –read-sector 300037184 /dev/sdb

And if it is the block and still fails:

hdparm –write-sector 300037184 /dev/sdb –yes-i-know-…

Obviously this zeros the sector and all 512 or 4096 bytes that lived at that place are gone forever, and give way for fresh zeros from a spare, remapped reserve block.

Use only when you know what you are doing, your milage may vary.

Update: If you init a fresh Linux MD RAID, you may want to increase the min speed limit to get things going into production a bit faster:

echo 100000 > /proc/sys/dev/raid/speed_limit_min

Update2: If you are running in some error correcting RAID mode (e.g. not striped RAID 0 ;-) the Linux code will apparently re-write sectors and thus already automatically trigger a remap of those sectors:

end_request: I/O error, dev sdb, sector 301373665
ata2: EH complete
raid1:md0: read error corrected (8 sectors at 301373600 on sdb1)
raid1: sdb1: redirecting sector 301373600 to another mirror

Recompress Update 17.11

Monday, November 27th, 2017

After releasing our initial PDF Re/compress we received praise by first customers and users - and one popular questions: Can you actually reduce the quality much, much more?!

Our initial Re/compress will go thru all the PDF’s objects, and re-writes them in a much more compact and compressed way and also potentially recover and fix some broken files. It would also allow to reduce compression quality and down-sample the image’s resolution.

However, some interested inquires intentionally wanted way worse, smaller, and thus faster to load files. One of the most popular reason? AutoCAD CAD drawing! Those users usually use some print to PDF driver that usually results in tens (if not hundreds) of thousands of vector segments, but also potentially many small, few pixel sized (inline, sigh) image dots from 3d renderings and such. Those would usually not compress very much in our original version. This files also actually cause popular PDF viewers, like Apple’s Preview and naturally even more so Adobe’s Acrobat to hang while it was drawing all this many page content for seconds - panning and zooming was also not a very snappy affair.

Meet Re/compres 17.11 - our first major update: A newly developed “Rasterize pages to bitmap graphics” pass will convert this huge amounts of objects to just a single, highly compressed image. Using the down-sample resolution option you can create a new compressed file, intentionally with “photocopier” like reduced quality. Particularly useful when you want to mail documents to public tenders and potential clients without them having to expose all the fine, zoomable details of the original vector file!

We hope Re/compress and all its features can help you in your daily office workflow, and if you have any other wish or inquiry just let us know, too!

Re/compress PDF.

macOS High Sierra

Monday, September 25th, 2017

The silly name aside (sigh), it is really ridiculous that in 2017 Apple does still not allow us to update the last Beta build to the GM (Golden Master) via a delta update, and instead forces us to download and re-install the whole OS from scratch, again.

Not only for developers this really is a total waste of time (and bandwidth). There are already hundred small design details all over macOS and iOS that are not 100%ly right in the Apple eco-system anymore, this additional annoyances really add up to a way too long list in the meantime!

Testing the Beta on my 15″ Retina MacBook Pro (Late 2013) the graphic performance (e.g. editing videos, but also just browsing the web) was quite sluggish, stability awful, and there was even screen flicker and corruption during booting (hello? - where has atomic mode setting gone? ;-)

The machine run also significantly hotter and battery life was obviously much worse. If Apple did not hot-fix this in the last weeks before the GM release this might very well be the worst macOS release I witnessed to date :-/ #peakbugs

Update: after fresh installation (sigh), even the boot graphic glitches prevail:

A post shared by RenéRebe™ (@renerebe) on

Update: even the Arstechnica mentions “bugs” 9 times, and “issues” 10 times, too. Nobody would have let Microsoft get away with this, and we would have called it the worst Windows Vista release ever, … Just saying, …

Update2: iMovie still has the same problem as the latest beta installation before the GM. On my above mentioned 15″ rMBP with 4k display connected and internal display closed iMovie even crashes straight away on start-up:

Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0×0000000000000000, 0×0000000000000000
Exception Note: EXC_CORPSE_NOTIFY

Application Specific Information:
-[QCCGLRootContext minimalSharedContextForCurrentThread]: Inconsistent state
abort() called

Surprisingly iMovie starts when I open the internal display in addition to the external 4k display. What?

Sick & sad. Really sad.

Update 5/11/’17 this is still not fixed in the macOS 10.3.1 and iMovie 10.1.8 and not 4k related, also happens with an vintage 20″ Apple Cinema Display, :-/ ..! #peakbugs

Update 6/12/’17 this is still not fixed in the macOS 10.3.2

The different kinds of Wake-on-Lan

Sunday, September 24th, 2017

Some time ago I posted about wake on lan being hidden by a cryptic energy BIOS option. This week I was setting up a new test system and wondered what exactly the Linux ethtool:
Supports Wake-on: pumbg
letters actually meant. The man-page is help and it actually is quite simple and logical:

p Wake on PHY activity
u Wake on unicast messages
m Wake on multicast messages
b Wake on broadcast messages
a Wake on ARP
g Wake on MagicPackettm
s Enable SecureOntm password for MagicPackettm
d Disable (wake on nothing). This option clears all previous options.