List of (mostly DB-related) Blogs

Here is a list of blogs that I find useful to consider if you are interested in DBMS developments:

• DBMS2 by Curt Monash - analyst's blog and as such a mix of technical and commercial analysis
• DBMS Musings by Daniel Abadi (assistant professor at Yale) - academically oriented blog but still tracking industry developments
• Database Column by folks around Vertica like M. Stonebraker, D. DeWitt et al. - mostly technical but partially promoting Vertica's products
• CACM blogs - wild mix of computer science topics
• 10x Software Development by Steve McConnell (author of Code Complete) - some good articles on software engineering; others mainly promote services of his consulting firm

Overview of my SDN Blogs 2008/2009

The complete list can be found here. These are the ones from 2008-2009:

Performance Study: Web Intelligence on top of SAP BW
(11 November 2009)

This is a kind of sequel to the blogs I've posted earlier this year. A long-term SAP customer provided real-world example that shows the performance improvements that have been achieved through the joint efforts of the WebI, ODA and BW development teams.

Comparing SAP BW and an Oracle DW
(14 April 2009)

This blog looks at the situation of a customer who migrated his hand-crafted Oracle data warehouse to SAP BW. It is a tangible, real-world case that contradicts many of the alleged pros and cons of the differing approaches to data warehousing. Beside TCO, the new SQL interface on SAP BW allows even for a surprising 1:1 comparison regarding query performance.

Faster Universe-Based Access To BW via MDX
(16 March 2009)

Business Objects's semantic layer can expose cubes as OLAP universes to client tools like WebIntelligence (or WebI for short). This applies to OLAP servers like Microsoft's Analysis Services or Hyperion's Essbase but also to SAP BW. There is a component called OLAP Data Access (ODA) that retrieves data via MDX - a query language for multi-dimensional data sources. In the case of BW, the ODA component connects to BW's OLAP BAPI. This connection has now been optimized and streamlined in order to improve the interoperability. This blog gives some insight in what has been done and what the effects are. It complements the blog on the two options to access BW data via universes.

SQL Access to BW via Data Federator
(6 March 2009)

In another blog, a number of improvements have been discussed regarding universe-based access to BW infoproviders. One major new option is that it is now possible to access BW infoproviders via SQL. Technically, this has been achieved via Business Objects's Data Federator (DF) that includes SQL engine running on top of federated data sources - one of those can be a BW 7.01 system. This blog provides some more insights into that approach.

Better Performance For Universe-Based Access To BW
(6 Mar 2009)

This blog introduces two new pieces of development shipping with BW 7.01 SPS3 that significantly improve the performance when using Business Objects WebIntelligence on top of NW BW.

Native Excel 2007 On Top Of Netweaver BI 7.0
(29 January 2008)

Using Excel in the context of BW is nothing new: (1) there is BEx Analyzer and (2) there is the native pivot tables inside Excel that connect via OLE DB for OLAP (ODBO) to BW. While (1) has mostly been the option of choice, option (2) has tended to be sidelined. The latter is significantly changed with Excel 2007 and NW BI 7.0.

Linksys WRT54G router as a repeater in an existing LAN

This is yet another chapter of my home networking experience. It has taken me some time to figure out this (fairly simple) procedure. So I'm summarizing it here in case someone else intends to do the same thing, namely to add another router to your existing home LAN, e.g. due to the lack of free ports (on your existing routers) or as you want the additional router to cover areas that are currently not covered by the existing WLAN. So, this is what you need to do:

1. Most important thing: link the router up not via the WAN port but via one of the LAN ports.
2. Disable DHCP on that router.
3. Set the WRT54G to router mode instead of gateway.

By the way: I believe that this works similarly with other routers and is thus not restricted to this Linksys model.

Web sites for running competitions

Unregularly, I participate in running competitions and I somehow like to try to join one when I'm abroad in order to see how things work in the respective country. So here is my collections of links:

• Germany
  • Hockenheimringlauf
  • Laufkalender (Lauftreff.de)
  • Laufkalender (DLV)
  • Laufkalender im Dreiländereck Südbaden - Elsass - Nordwestschweiz
• Spain
  • Somesport
  • Noupindaro
  • Tiramillas
• US
  • Running USA - click on Event Calendar
  • Active.com
  • Athlinks.com

3G (UMTS) and GPRS Settings for Germany

Here is a great page describing the configuration necessary to access the internet via the most popular German mobile network providers. Extremely helpful.

Vodafone UMTS Laptop Karten Einstellungen

APN	web.vodafone.de
IP-Adresse	dynamisch
Primärer DNS	139.7.30.125
Sekundärer DNS	139.7.30.126
Einwahlnummer	*99***1#
Benutzername	-
Passwort	-
AT-Kommando	AT+CGDCONT=1,"IP","web.vodafone.de"

UMTS Verbindungs-Software Vodafone

T-Mobile UMTS Laptop Karten Einstellungen

APN	internet.t-mobile
IP-Adresse	dynamisch
Primärer DNS	193.254.160.1
Sekundärer DNS	-
Einwahlnummer	*99#
Benutzername	frei wählbar
Passwort	frei wählbar
AT-Kommando	AT+CGDCONT=1,"IP","internet.t-d1.de"

UMTS Verbindungs-Software T-Mobile

O₂ UMTS Laptop Karten Einstellungen

APN	surfo2
IP-Adresse	dynamisch
Primärer DNS	62.134.11.4
Sekundärer DNS	195.182.110.132
Einwahlnummer	*99# oder *99***1#
Benutzername	-
Passwort	-
AT-Kommando	AT+CGDCONT=1,"IP","surfo2"

UMTS Verbindungs-Software o2

e-Plus UMTS Laptop Karten Einstellungen

APN	internet.eplus.de
IP-Adresse	dynamisch
Primärer DNS	212.23.97.2
Sekundärer DNS	212.23.97.3
Einwahlnummer	*99***1#
Benutzername	eplus
Passwort	GPRS
AT-Kommando	AT+CGDCONT=1,"IP","internet.eplus.de"

UMTS Verbindungs-Software e-Plus

3G (UMTS) Internet Connection via a Simyo SIM Card in Spain

So, this is my most recent "IT experiment": for years, I've been wondering how to have a decent (acceptably fast) internet conenction in my parents' house in Spain. Obviously, you can get DSL and stuff there too. However, as the house is occupied only during 2-3 months per year there would be too much of stand-by costs involved. Finally, I've found a non-expensive way to achieve what I've been looking for. This blog describes what I have installed in case someone else is interested and wants to do the same or something similar.

Here are the "ingredients", i.e. the equipment, I've used:

• a T-Mobile webnwalk Box IV - approx. €133
  • This is a LAN / WLAN router
  • It connects to the internet via 3G (UMTS) or GPRS (in case that the 3G signal is too weak) by using a SIM card.
  • Not so important but useful: a normal, analog fixed-line phone can be plugged in too so that you can use the phone + router as a normal phone.
• a prepaid SIM card from Simyo Spain
  • Simyo currently offers 100 MB/day for €1 or 500 MB/month for €5.
  • Beware that things become more expensive once you pass the 500 MB/month threshold.
  • If the signal allows the connection is 3G.

So what do you need to know in order to configure the 3G router:

• APN: gprs-service.com
• phone number: *99#
• Leave name and password blank
• As the PPP authentification method use CHAP. Please note that this is not the default but this is essential. Otherwise it won't work with Simyo in Spain. It is different with Simyo in Germany.
• Here is good description (in Spanish) on how to connect to the internet via Simyo.

Ok. I hope this works for you. Let me know if you have any comments or advice on how to improve this setup.