macrabbit

Small PCs

I think desktops are dead! In the future, everybody will have a laptop because the benefit of mobility convinces. See the cellular phones; they superseed the fixed ones. The still existing gap between portable laptops and desktops (pricewise and performancewise) will be closed. I so strongly believe in this idea, that I only bought laptops lately. At the moment, I have two laptops:
MacBook Pro and Vaio TX3XP

(I sold my previous Powerbook G4 and my Vaio TR1MP on ricardo.)

To be portable, the laptops have to be thin and light. The CPU, the memory, the HD: everything shrinks to unbelievable size. Connectors disappear being replaced by wireless interfaces instead. But input/output devices - I mean keyboard and screen - can not shrink indefintely as my fingers and my eyes have physical limitations. And my fingers and eyes get worse, remember: even I get older :-) . The keyboard and screen can share the same area e.g. by touch screen technology. So, the main size limitation of a future laptop will be the size of its screen.

From time to time, I do some "market research" to see what technology has to offer. I'm looking at PCs (not PDAs) with small but sharp (see below) displays. Here a list of small gadgets:
* Sony VGN-UX50, 4.5", 1024x600, 263 PPI
* Sony VGN-U50, 5", 800x600, 200 PPI
* OQO model 01+, 5", 800x480, 186 PPI
* Panasonic Libretto U100, 7.2", 1280x768, 207 PPI
* Motion Computing LS-800, 8.4", 800x600, 119 PPI
* Dialogue Flybook V33i, 8.9", 1024x600, 133 PPI
* Fujitsu P1510, 8.9", 1024x600, 133 PPI
* Fujitsu T70R, 10.6", 1280x768, 141 PPI
* Sony Vaio TR1MP, 10.6", 1280x768, 141 PPI
* Sony Vaio TX3XP, 11.1", 1366x768, 141 PPI
* ASUS S6F, 11.1", 1366x768, 141 PPI
* Apple MacBook Pro, 15.4", 1440x900, 110 PPI
* Apple PowerBook Titanium, 15.2", 1152x768, 91 PPI

Graphic resolution

In the PC industry, I often read the "size" of digital monitors are referred to by names: VGA, SVGA, XGA, WXGA, UXGA and so on. In my point of view, these names describe neither the "size" nor the "resolution" of a screen. It simply counts the number of pixels. In my point of view, the "size" is determined by the physical dimension (inch or centimeters), and the "resolution" or "sharpness" is defined by pixels per size. To be precise, an additional value must be given: the "pixel aspect ratio" (PAR) important if pixels are not square (see DVD standard). But on most computer screens these days pixels are square, so let us forget the PAR at the moment.

In digicam industry, it is quite "normal" to quote the so called megapixel. Let me quickly summarize: VGA = 640x480 (0.3 MegaPix), SVGA = 800x600 (0.5 MegaPix), XGA = 1024x768 (0.8 MegaPix), SXGA = 1280x1024 (1.3 MegaPix), UXGA = 1600x1200 (2 MegaPix). If we only knew the size of a pixel... The smaller the pixel, the sharper the image (Do you know the Sharper Image?). Or to turn it around: the more pixel per inch (=PPI), the better. Silly enough: PC industry didn't discover the "PPI" as marketing instrument yet. They boost the MHz to GHz, they love to talk about Gigabyte or Terabyte of hard disk space, but they don't mention the PPI, the thing an end user can see. Whenever I discover a new computer, the first thing I do is calculating the PPI. Good old Pythagoras..

That's cool: 300 PPI. Even cooler: 400 PPI

How many PPI do I see?

First of all, the needed resolution for a sharp picture is dependent on the viewing distance. In addition, the resolution also depends on the picture's contrast. But let's neglect the contrast for the moment. I found different sources for our eye's resolving power (or more academic: the visual acuity [VA] of the human visual system [HVS]).
* 1 arc min --> 60 arc sec/pix
* 30 lp/degree --> 60 arc sec/pix
* 4 lp/mm @ 1 foot distance --> 84 arc sec/pix
* 6 lp/mm @ 25 cm distance --> 68 arc sec/pix
* 4-8 lp/mm @ 10" distance --> 50-101 arc sec/pix
As a line pair consists of 2 pixels, we get the following formula: lp/mm * 50.8 = PPI. The diagram below shows the resulting PPI for a resolving power of 50 (=better), 60 (=normal) and 70 (=worse) arc sec:

Is a 6 Megapixel digicam better than a 3 Megapixel digicam?

Simple answer: Not necessarily. Let's have a deeper look at CCD sensor - Bayer vs. Foveon mask.

SMS to fixnet

I bought the "Siemens Gigaset S150" before Swisscom offered the SMS to Fixnet service. So I had to program the SMS-center number myself. Neither on the Swisscom web page nor in the Gigaset manual I could find the relevant data. Here it is: SMS-center=<062 210 000*> The <*> as last digit is important as the Gigaset supports different inboxes for SMS. To check whether everything is working, just send an SMS with *oksms# to 8888. You'll receive a greating. Another remark: "Normal" phones - not capable to handle SMS - will ring once before the Gigaset will hook off and receive the SMS (Annoying if the SMS enters during you sleep!)

Alcatel One Touch 835: configuring GPRS for Orange Switzerland

Cellular phones can work in two modes: 1) surf the internet with the built-in browser or 2) act as a GPRS modem for a PC. If you configured the GPRS parameters for 1) correctly, it's normally enough to dial *99# from a PC to get 2) working as well. This does not work for the Alcatel OT 835 :-( The solution is to define an own GPRS profile (PDP context) via modem commands and activate it while dialing:

* APN: internet
* TCP/IP settings: DHCP
* Modem init command: +CGDCONT=1,"IP","internet";+CGQREQ=1;+CGQMIN=1
* Dial string: *99***1#

RDS

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RFID

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Encryption

...PKI