umount: /mnt/tmp: device is busy permalink
If you are trying to unmount a device, you get the error "device is busy", but lsof/fuser don't show any process holding the device open, it could be that a file on the device is associated with a loop device.
# losetup -a /dev/loop/0: :25280514 (image) offset=55273881600 # losetup -d /dev/loop0 # umount /mnt/tmp(updated, 2016-11-01)
dmsetup info | grep loop dmsetup remove loop0p2 dmsetup remove loop0p3may help too
More hints on unmounting a filesystem: permalink
# ls -l /dev/mapper/ # dmsetup ls # dmsetup info loop0p2 # dmsetup remove loop0p2 # losetup -a # losetup -d loop0 # umount /mnt/tmp
Windows Security Applications (2007-12) permalink
(updated for Malwarebytes, 2016-02-04) When working with friend's PCs, here are some applications I install:
- Secunia PSI Personal Software Inspector
- (Added 2013-03-04) Filehippo Update Checker
Colleagues also recommend Ninite
reviewed at The Register
- Grisoft AVG free anti-virus
Lavasoft Ad-AwareNot any more - see this article (2011-11-13)
- (added 2008-02-10) And one more link: Windows Sysinternals
- (Added 2011-12-27) SANS ISC recommend MalwareBytes free anti-virus, OTOH: security issues,
- (Added 2013-03-04) The UK government's advice
Hints on running a well-configured outgoing mail server. permalink
If you do not have a static IP address, use your ISP's
mail relay (smarthost).
Make sure that there is a reverse DNS (PTR) record for your
IP address. Make sure that it is not generic (e.g. wylie.me.uk,
rather than client-12-34-56-78.adsl.example.org). You will need
to contact your ISP to do this. (See RFC1912 section 2.1)
Make sure that doing a PTR lookup, then doing an A lookup on that domain name gives the original IP address, e.g.
$ host 188.8.131.52 184.108.40.206.in-addr.arpa domain name pointer wylie.me.uk. $ host wylie.me.uk wylie.me.uk has address 220.127.116.11
Get your ISP to SWIP your IP allocation, so that a whois lookup shows
that it is allocated to you.
Make sure that your ISP has not listed your IP address as dynamic with
any DNSBL, e.g. dul.dnsbl.sorbs.net. If necessary, get your ISP to contact
the DNSBL maintainers and ask for your IP address to be delisted.
- Make sure that your HELO/EHLO string is a FQDN (Fully Qualified Domain Name), e.g. "wylie.me.uk", rather than "NTSERVER", as required by RFC 2821 section 18.104.22.168
Spamhaus reverse DNS
Spamhaus Dynamic IP lists
Yahoo mail help
AOL Technical Standards for E-mail Delivery
AOL Reverse DNS
Messaging Anti-Abuse Working Group Sender Best Communications Practices
If you get errors trying to nfsmount your root partition during a PXE boot permalink
VFS: Unable to mount root fs via NFS, trying floppy. VFS: Cannot open root device "nfs" or unknown-block(2,0): error -6 Please append a correct "root=" boot option; here are the available partitions: Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)try adding "nfsvers=3" to your kernel command line
LABEL alan KERNEL alan/bzImage APPEND root=/dev/nfs nfsroot=192.168.21.1:/work/netboot/alan/nfsroot,nfsvers=3 \ ip=dhcp nfsrootdebug vga=0x323 email@example.com/,@192.168.21.2/
Gentoo, bash, xmalloc errors permalink
In Gentoo, after turning on the bash use-flag "mem-scramble", I got emerge errors for icu and nmap:
bash: xmalloc: shell.c:1596: cannot allocate 10 bytes (0 bytes allocated)
Just to try and g**gleb*mb it: permalink
Link to a friend's NHS Anti Smoking Campaign
About me: permalink
I'm a computer hacker (in the original meaning of the word), a caver, a fell-walker, and cyclist.
mail me at firstname.lastname@example.org
Note that sending unsolicited marketing e-mail to an individual in the UK is an offence under the Privacy and Electronic Communications (EC Directive) Regulations 2003 and that the collection and processing of personal information is regulated by the Data Protection Act.
Contact Me permalink
Please note that sending unsolicited marketing e-mail to an individual in the UK is an offence under Section 22 of the Privacy and Electronic Communications (EC Directive) Regulations 2003 http://www.legislation.gov.uk/uksi/2003/2426/regulation/22/made
If you are having difficulty e-mailing me, perhaps because of my anti-spam defenses, use this form (See also Hints on running a well-configured outgoing mail server )
Xmas links permalink
UWFRA SARDA BPC Gaping Gill Titan Titan Titan Titan
Captain Brown's Experience on board the barque Robert Hine permalink
My brother David has scanned in and OCR'd a pamphlet my Great^2 Grandfather published entitled Captain Brown's Experience on board the barque Robert Hine
Found, at the summit of Puig des Tossals Verts, Mallorca, on Wednesday 9th November 2011. permalink
A Panasonic Lumix DMC-TZ18 Camera
Contact me for the contents of the SD card and the return of the camera.
Lateral Cleft, Jingling Pot permalink
Confusing Apache error message permalink
If you get the following error message:
[crit] [client 10.0.0.1] (13)Permission denied: /foo/bar/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable, referer: http://example.org/
check that the permissions on the directory enable the web server user to read/access it, to fix it do something like:
find <dir> -type d | xargs chown <apache user>
find <dir> -type d | xargs chmod u+rx
(Updated April 2010)
I've found a new job.
My excellent ISP: Zen Internet
A very nice Bed and Breakfast in Coniston:
Oaklands Guest House
Unsolicited Bulk Commercial e-mail from Janglemail / Blurbjangle permalink
Full story here
Laser-Scan Fastrak permalink
A photo of the Laser-Scan Fastrak display and digitiser, circa 1985. Click to enlarge.
The Hine Line of Maryport permalink
Here are some scans from the Magazine "Sea Breezes", September 1959
Mallorca photographs permalink
Sunday Monday Tuesday Wednesday Thursday Friday