I found an undocumented feature in Cisco IOS 11.2.
The command “show interface description” exists in newer versions, so I typed it in out of habit. Even though it doesn’t tab-complete it, or know what that option to the sh int command is, it still works… Albeit badly, and it gives terribly formatted output (All on one line, no spaces between names, no blank spaces where unlabeled ports are, etc)
It still works though! :-)
Makes me wonder how many undocumented features exist in versions of IOS earlier than they are supposedly “released”.
drpepper#sh ver
Cisco Internetwork Operating System Software
IOS (tm) C2900XL Software (C2900XL-HS-M), Version 11.2(8.10)SA6,
MAINTENANCE INTERIM SOFTWARE
Copyright (c) 1986-1902 by cisco Systems, Inc.
Compiled Fri 15-Feb-02 09:47 by devgoyal
Image text-base: 0x00003000, data-base: 0x0020E278
...(rest of output truncated for brevity)
drpepper#sh int ?
FastEthernet FastEthernet IEEE 802.3
Null Null interface
VLAN Switch VLAN Virtual Interface
accounting Show interface accounting
crb Show interface routing/bridging info
irb Show interface routing/bridging info
link-trap Show interface traps on no link
drpepper#sh int desc
Blacktea LinkCSH UplinkJolt ManagementRESNETRESNETRESNETRESNET
November 15th, 2009 in
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I got very bored in a far-too-easy networking class and ended up coding a very memory efficient version of Conway’s Game of Life.
Of note, it uses bit-twiddling/bit-packing to access individual bits on byte-accessible memory for the gameboard, and it uses a sort of buffer-thing to further reduce memory usage, rather than push temporary changes into an entire other temporary game board. I just made it up as I went along. The idea behind being this memory efficient is so that I can plop this on a microcontroller (possibly CSH’s Big Infosys?) and just let ‘er rip on a LED matrix :-)
Source is up at http://github.com/clockfort/Life/
I decided to redo the NFS setup I previously had on my ol’ Itanium2 machine.
Standard disclaimer: These tests were run with purposeful cache prevention techniques so that caching would not make all subsequent tests faster, yada yada, I am not retarded.
Specs:
2x 1.5GHz Itanium2 processors
10GB ECC DDR
3x 74GB 15k RPM U320 SCSI drives in RAID5
Gigabit ethernet
I am somewhat confused as to why the NFS write performance is so appalling, while the read performance approaches the theoretical maximums of a gigabit ethernet connection.
Any advice on improving write performance over NFS would be much appreciated.
(Graph is here if you’re reading this post without images)
I propose that this is the best Ubuntu Netbook Remix Firefox setup ever.
Uses:
Simply binding both of these plugins to activate with the left alt key is working out deliciously well. It’s a small screen, but with some tweaks like these, the lack of real estate isn’t as much of a problem, and I can continue enjoying the crazy portability that is my EeePC 1000HE, and not have to scroll through every webpage to get down to the information I want to read. Plus, it looks pretty sexy with the new minimalist-themed Google :-)
(Screenshot is here if you’re reading this post without images) 
October 19th, 2009 in
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VirtualBox, while I like the interface and it has a few features that are lacking in VMWare and other virtualization products, has many issues.
First off, it doesn’t quite implement the x86 instruction architecture perfectly.
Secondly, this is terrible:
VirtualBox Trouble Ticket #192
VirtualBox Trouble Ticket #639
Basically, Sun has insisted for years that VirtualBox emulates OpenBSD perfectly and yet, it has been completely broken for years and they have not only not fixed the bugs in their own application, but have also not stopped insisting that it works just fine. Theo has posted a rant or two about how Virtualbox’s emulation sucks, and how he has wasted time tracking down non-existant bugs because of users repeatedly filing bug reports for segfaulting software when it is in fact just VirtualBox’s shitty emulation; I’m starting to see why he has this opinion.
Seriously, do not use VirtualBox to emulate OpenBSD (or !any! Unix other than Solaris). Everything is broken. Go try QEMU or VMWare.
But, if you want to try it anyway, here’s the settings you’ll NEED to have. Other settings are left up to your own options.:
General
OS type: OpenBSD
System
VT-x/AMD-V: Enabled*
PAE/NX: Enabled
Nested Paging: Disabled
Display
Video memory: 32MB
Hard Disks
IDE Controller Type: PIIX4
Network
Adapter: Intel PRO/1000 T Server
*obviously this is not possible if your host OS/CPU does not support it. OpenBSD segfaults less with it enabled. It runs(…ish) with it disabled.
tl;dr: VirtualBox is an excellent desktop virtual machine software, especially with its new features, like its 3D-rendering pass through technologies, and many-CPU SMP support. It is a terrible server virtual machine software, and is buggy, cannot run any unix distribution properly, except Sun’s own Solaris 10 kool-aid.
Here’s to you, blog viewers of this last month. I’m fairly sure this isn’t the normal OS distribution… You guys are awesome. :-)
Initially I thought the OpenBSD must have been me, as I run it on my router (yay pf!), but then I realized I don’t even have a browser installed on it… really can’t have been me, I guess. You know what that means? There are at least two users of OpenBSD! Alright! Party!
August 23rd, 2009 in
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Writing code for this OS class reminds me of why I only write C++/java/ruby nowadays, rather than C.
Here’s a snippet from the top of one of my main files… I do enjoy making C languages that it is not!
// Look, I really like C++; I'll be needing these :-)
#define true (1==1)
#define false (!true)
typedef int bool;
//Debug mode toggle
const bool DEBUG_MODE=true; //See? Already using 'em!
(15:09:56) Andy Potter: Friday night the 3rd turns into 2x holidy pay at the stroke of Midnight. Make sure they don’t screw you.
(15:10:19) Me (AIM): Hmm, 2x holiday pay with C-Shift adjustment = $$$$$$$$$
(15:10:55) Andy Potter: what is C shift these days? before it was only .50 /hour
(15:11:24) Me (AIM): 50 cents an hour
(15:11:26) Me (AIM): inflation is awesome
(15:11:42) Andy Potter: Its been that since 1982
(15:11:46) Me (AIM): … nice.
… Gorram it.
So, I successfully managed to broadcast a “cshnowires-psk” network from my makeshift router. However, the encryption of the tunnel between the networks is NOT making my router’s 200MHz MIPS CPU happy – in fact, it’s maxing out at around 50KB/s with a strong wind behind the back of the bits.
Looks like I’ll have to have a Real Machine (TM) to do the encrypt/decrypt of network traffic so I can see an actual 100mbit link. It’s not so bad, really; I think I’ll kill two birds with one stone and create a media center/VPN gateway box out of an old machine (A P4) using linux, mythtv, and either vpnc or openvpn.
Breaking weeks of blog-o-silence for this update…
I recently moved from RIT’s dorms to an apartment I share with some CSHers. Unfortunately, among the wide variety of amenities offered, wireless Internet is not one of them.
Unfortunately, I’ve been very spoiled in terms of networking hardware, having worked with Cisco’s product line, and I find it painful and miss the features when I’m using consumer-grade electronics. Unfortunately, Cisco wireless technology costs an arm and a leg.
The solution? I purchased a Linksys WRT54GL, a device specifically designed for people to use their own linux distros on. I put on OpenWRT, which gave me a variety of commercial-grade options for a pittance of the price.
I’m broadcasting a few SSIDs – a WPA2-Personal network for apartment mates to have their own little network (Opcom-Net-Internal), a WPA2-Personal network that ust acts as as WAP for my apartment’s wired network (Opcom-Net-External), and a WPA2-Enterprise network that uses OpenVPN and some kludging together in order to provide a seamless connection to CSH’s network (cshnowires-eap). (That last one isn’t quite working yet, but I’ll work on it more after I change some things that need changing on CSH’s own wireless; no use configuring things twice for a new setup) This could simply not be done without multiple SSID broadcasts, VPN, RADIUS, VLANs, and a variety of other enterprise-only features that one could simply not get for the $50 I paid for this network device. Amazing. Highly recommend this device; the only downside is that it’s wireless-G, and not N, and that there is not a whole lot of flash/RAM for programs, but this comes with the embedded territory.
Following my usual naming scheme, the hostname for this device is “Dr. Bob”, which fits especially well considering it’s plugged into my Cisco network switch “Dr. Pepper”. The good doctors are quite kind on my network :-)
