Showing all posts tagged howto:

How to Rip a GeoTIFF Off Google Maps

Google Maps allows you to view satellite imagery at various resolutions via a web-based interactive display. The maps are transferred as partial tiles, making access quick as it only downloads the parts you need as you to pan and zoom. You can take a snapshot of the screen using your operating system's Print Screen feature, but what if you wanted a high-resolution image that covered an area larger than your screen? And what if you needed the image to be geo-referenced? Google Satellite Ma...

Setting Up Reverse FTP Proxy Server

Setting Up a Reverse FTP Proxy Server Problem: You have a server (let's call it the firewall) with a public IP. Users will connect to this public IP using FTP clients. However your actual FTP server is not located on the firewall, but located somewhere else -- behind a DMZ, or through a VPN, or just another "less visible" public IP on the internet. You need the Firewall to act as a reverse-proxy and relay the protocol from your firewall to your actual ftp server. Doing this at the network ...

How To Crimp DuPont Connector Pins

How to Crimp DuPont Connector Pins These are DuPont connectors: They consist of metal pins or (more commonly) sockets, that fit into a plastic casing, and are used to connect individual wires to header-pins on a PCB. You've probably seen them to connect the speaker, power supply and LEDs on your PC casing to the motherboard. Up till now, I've been attaching wires to the metal sockets by soldering and/or "crimping" them using a pair of thin-nosed pliers. You can "kind of" secure it in thi...

Expanding Virtual Machine Disk

Situation: I had originally created one of my QEMU/KVM Virtual Machines with a qcow2 format disk image of 25GB. I realised I needed more space on my /data partition. mount: /dev/mapper/vg_icky-lv_data on /data type ext4 (rw) lvscan: ACTIVE '/dev/vg_icky/lv_data' [12.54 GiB] inherit pvscan: PV /dev/vda2 VG vg_icky lvm2 [24.51 GiB / 0 free] The VM's disk resides on the host at: /raiddata/VMRAID/icky.img This is what I did:stop the virtual machine.On the host, execute the following: qemu-im...

MySQL Notes

MySQL Here are my notes for MySQL on CentOS 5.Install MySQLInstall mysql:sudo apt-get install mysql-server (Ubuntu)yum install mysql mysql-server (CentOS)For cluster systems:Move mysql data folder to shared storage:mv /var/lib/mysql /data/mysqlln -s /data/mysql /var/libFor non-clustered system, start mySQL on boot:chkconfig --level 345 mysqld onStart mysql service. Note that on ubuntu, the service name is "mysql" but on CentOS it is "mysqld":service mysqld startSet initial root passwordRun sc...

Treo Ringtones

Almost everyone around me has a Samsung phone and I got tired of needlessly checking my phone each time someone else received a call or message. I found that someone had put up the MIDI ringtones from the Treo 600 and 650 series of yesteryear, so I decided to Go Retro! You can find download the MIDI files from here: http://forums.crackberry.com/blackberry-ringtones-f15/palm-treo-ringtone-216856/. MIDI files don't record the actual sound played, rather they store the notes played and what i...

PostgreSQL Tips and Tricks

Initial PostgreSQL Setup (Ubuntu 12.04)I change the access control porton of the /etc/postgresql/9.1/main/pg_hba.conf to the following:# Database administrative login by Unix domain socket local all postgres peer # TYPE DATABASE USER ADDRESS METHOD # "local" is for Unix domain socket connections only #local all all peer # IPv4 local connections: #host all ...