Review: Blockchain for dummies

The book "blockchain for dummies" provided by IBM contains 6 chapters on 41 pages. (Download from IBM)

The chapters 1 & 2 describe the basic of blockchain technology.
From my point of view, this part is a bit too shallow, because there is no single formular inside this book ;-)
But there are some nice illustrations given:

and the differences between a public blockchain and corporate blockchains are good explained including their  consequences.

Chapter 3 is about where companies can use blockchains. This chapter i did not understand. It is all about frictions which companies have to overcome. But these frictions are not special to blockchain (like "innovation restrictions").

In chapter 4 some examples are shown. These examples are very universal examples, which are too abstract in my eyes.

Chapter 5 contains information about a project of the Linux Foundation: Hyperledger.
This is very nice opening for https://www.hyperledger.org/.

Chapter 6 comes up with ten steps to your first blockchain application.
Skippable.

My conclusion: a very nice book and really ok for free. But I wouldn't spend any money on it...

Openafs on Debian (Configuration)

A few days ago a friend asked me, how to install openafs on a Debian Linux. I told him, that he just has to follow my article on www.debianplanet.org...
But on www.debianplanet.org he only got the following information:
Temporarily removed due to spammers, read-only archive version will be back after reconfiguration.


So i searched in my files and finally i found my article:
Submitted by dschroff on Friday, November 01, 2002 - 23:59

Here the content:

This is a quick and dirty rundown of how to install OpenAFS and Kerberos 5 and get it all working. OpenAFS is a pretty advanced and rockin' distributed filesyste; for more information, check out openafs.org.
As an absolute minimum, you'll need to install the following packages:

libpam-openafs-session
openafs-client
openafs-krb5
openafs-modules-source
libkrb53
krb5-clients
krb5-config
krb5-doc
krb5-user
libpam-krb5
openafs-krb5

If you're running a server, you'll also need to install the following packages.

openafs-dbserver
openafs-fileserver
krb5-admin-server
krb5-kdc

Secondly, you'll need to set Kerberos up. Read and follow the instructions in /usr/share/doc/krb5-doc/install-guide.ps.gz and create a user called admin.
After this, you'll need to build the OpenAFS module. Extract the /usr/src/openafs.tar.gz file and
read /usr/src/modules/openafs/debian/README.modules; this will create the package and tell you how to install it.
After you're built OpenAFS, you'll need to configure this. First, edit /etc/openafs/ThisCell to set your domain name, then edit /etc/openafs/CellServDB, and add your server and domain. Copy these files to /etc/openafs/server and create a partition /vicepa for the data with a filesystem of your choice.
On the server, type:

#>kadmin.local -q "ank -randkey afs"
#>kadmin.local -q "ktadd -e des-cbc-crc:afs3 -k /etc/krb5.keytab.afs afs"
#>asetkey add foo /etc/krb5.keytab.afs afs
#>bosserver -noauth &
#>bos listhosts servername -noauth
#>bos create -server servername -instance ptserver -type simple -cmd /usr/lib/openafs/ptserver -cell domainname -noauth
#>bos adduser servername admin -cell domainname -noauth
#>bos listkeys servername -cell domainname -noauth
#>pts createuser -name admin -cell domainname -noauth
#>pts adduser admin system:administrators -cell domainname -noauth
#>pts membership admin -cell domainname -noauth
#>bos restart servername -all -cell domainname -noauth
#>bos create -server servername -instance fs -type fs -cmd /usr/lib/openafs/fileserver -cmd /usr/lib/openafs/volserver -cmd /usr/lib/openafs/salvager -cmd /usr/lib/openafs/vlserver -cell domainname -noauth
#>bos status servername fs -long -noauth
#>vos create -server servername -partition /vicepa -name root.afs -cell domainname -noauth
#>bos shutdown servername -wait
#>pkill bosserver
#>/etc/init.d/openafs-fileserver start
#>/etc/init.d/openafs-client start
#>kinit admin && klist
#>aklog && tokens
#>fs checkvolumes
#>fs setacl /afs system:anyuser rl
#>vos create servername /vicepa root.cell
#>fs mkmount /afs/domainname root.cell
#>fs setacl /afs/domainname system:anyuser rl
#>fs mkmount /afs/.domainname root.cell -rw
#>pts creategroup groupname -id -groupname
#>mkdir /afs/domainname/home

foo is the number of the key.
When you've done all this, it's time to add a user; you need a working NSS system for this. To add users, type:

#>adduser --disabled-password

To tell Kerberos and OpenAFS about your new user, type:

#>kadmin.local -q "ank -maxlife 30days username"
#>vos create servername /vicepa username
#>fs mkmount /afs/domainname/home/username username
#>vos release root.cell
#>fs checkvolumes
#>pts createuser username -id userid
#>pts adduser username groupname
#>fs sa /afs/domainname/home/username username all
#>fs setquota /afs/domainname/home/username -max 500000

Now you'll need to set up the /etc/pam.d files. Just play with the configuration files or send me an e-mail; even better, check out the debian-security archives.
Good luck!


Yes, i know there are better installation tutorials like this one, which is really excellent, but look at the references: [1] Installing OpenAFS, http://www.debianplanet.org/node.php?id=816 !!!!
I hope debianplanet will be back soon...

Review at amazon: Performance and Capacity Planning with BPEL

Some days ago i read the book "Business Process Automation. Performance and Capacity Planning with BPEL" .
First i was amused, but after 50 pages i got angry and decided to write a recension at amazon about this book. If you are interested take a look here.
The recension is in german (sorry), but here a short summary:

The assumptions, which are made in this book are too simple. Yes it worked for their sample process but in real world their model will fail...

And the best:
They invented a small test program to generate test messages and put some load on their BPEL-engine (Websphere). In Oracle this stress test (s. 5.) tool is out of the box integrated into the BPEL PM.

IBM supports Solaris

What a strange world...
Have you read this press release?

IBM promotes Solaris on its xSeries server. Wow...
First SCO looses its battle against Linux and now IBM sells Solaris on its servers. What will happen tomorrow?
AIX on SPARC? MacOS on Itanium? MS Office on PalmOS?

Everything is possible ;-)

The never ending story is ending? (SCO vs. Linux/IBM

Just fresh from www.groklaw.net:

Novell owns the UNIX and UnixWare Copyrights. This seems to be the end for SCO... No more license fees from other companies and the chances for the condemnation of IBM are vanishing.