Fivell's Whim » Electronics

iPod Diagnostic Menu

fivell — Wed, 17 Sep 2008 00:22:15 +0000

Memory:	The Memory tests include diagnostic procedures for your iPod’s SDRAM, IRAM and FLASH memory. SDRAM: The RAM memory test. The SDRAM Fulltest will take several minutes. A successful pass result is “SDRAM OK.” IRAM: Not sure exactly what this test does. It takes several moments to load before running a quick test and rebooting your iPod. FLASH: This test will do a checksum test of your iPod’s flash memory.
IO:	Comms: This tests the communication ports of your iPod including USB, FireWire and Remote. If the Remote is not connected to your iPod at the time of the test, you can expect a NG (no good) for the HP (headphone-port). Wheel: This option has two tests, Keytest and Wheeltest. Push each button once to pass the Keytest. The Wheeltest just gives you a coordinate of where your finger is on the Click-Wheel. : This option has two tests, Backlight (0 to 255; 128 is the default) and Color. Much like a VRAM test, the Color test will run through a series of colors, patterns and gradients. HeadphoneDetect: This test checks the Hold Switch and Headphone port. HardDrive: This option has four tests. HDSpecs will tell you everything from hard drive temperature to serial number. HDScan scans your iPod’s hard drive. This is a great way to see if you have a healthy iPod and if your hard drive is fragmented. This test will take a few minutes so be patient. HDSMARTData returns SMART data for professional repair applications and personnel. HDRW tests the ability of your hard drive to RW (read and write data). A FAIL result probably means you need to get your hard drive replaced. Audio: This option has two tests. Playback plays an audio sample to make sure your iPod can produce sound. MIC tests your iPods ability to record audio.
Power:	A2DTests: This test has multiple sub tests. PhilipsID checks the power system of your iPod A2D lists a series of A2D (analog to digital) tests.
Status:	Status displays the status of several of your iPod’s key systems. Sharp: LCD screen HP: headphones. Are they connected? [0 = no, 1 = yes] FWPWR: FireWire power. Is your FireWire cable charging your iPod? USBPWR: USB power. Is your USB cable charging your iPod?
SysCfg:	SysCfg: System Configuration. This lists your iPod’s hardware version, serial numbers, and part number.

Internet Protocol

fivell — Sun, 07 Sep 2008 21:05:34 +0000

IP Explained

IP Address (Internet Protocol Address): This number is an exclusive number all information technology devices (printers, routers, modems, et al) use which identifies and allows them the ability to communicate with each other on a computer network. There is a standard of communication which is called an Internet Protocol standard (IP). In laymans terms it is the same as your home address. In order for you to receive snail mail at home the sending party must have your correct mailing address (IP address) in your town (network) or you do not receive bills, pizza coupons or your tax refund. The same is true for all equipment on the internet. Without this specific address, information cannot be received. IP addresses may either be assigned permanently for an Email server/Business server or a permanent home resident or temporarily, from a pool of available addresses (first come first serve) from your Internet Service Provider. A permanent number may not be available in all areas and may cost extra so be sure to ask your ISP.

Domain Name Server (DNS): This allows the IP address to be translated to words. It is much easier for us to remember a word than a series of numbers. The same is true for email addresses.

For example, it is much easier for you to remember a web address name such as whatismyip.com than it is to remember 192.168.1.1 or in the case of email it is much easier to remember anonymous@whatismyip.com than anonymous@192.168.1.1

Dynamic IP Address: An IP address that is not static and could change at any time. This IP address is issued to you from a pool of IP addresses allocated by your ISP or DHCP Server. This is for a large number of customers that do not require the same IP Address all the time for a variety of reasons. Your computer will automatically get this number as it logs on to the network and saves you the trouble of having to know details regarding the specific network configurations. This number can be assigned to anyone using a dial-up connection, Wireless and High Speed Internet connections. If you need to run your own email server or web server, it would be best to have a static IP.

Static IP Address: An IP address that is fixed and never changes. This is in contrast to a dynamic IP address which may change at any time. Most ISP’s a single static IP or a block of static IP’s for a few extra bucks a month.

IP version 4: Currently used by most network devices. However, with more and more computers accessing the internet, IPv4 addresses are running out quickly. Just like in a city, addresses have to be created for new neighborhoods but, if your neighborhood gets too large, you will have to come up with an entire new pool of addresses. IPv4 is limited to 4,294,967,296 addresses.

IP version 5: This is an experimental protocol for UNIX based systems. In keeping with standard UNIX (a computer Operating System) release conventions, all odd-numbered versions are considered experimental. It was never intended to be used by the general public.

IP version 6: The replacement for the aging IPv4. The estimated number of unique addresses for IPv6 is 340,282,366,920,938,463,463,374,607,431,768,211,456 or 2^128.

The old and current standard of addresses was this: 192.168.100.100 the new way can be written different ways but means the same and are all valid:

* 1080:0000:0000:0000:0000:0034:0000:417A

* 1080:0:0:0:0:34:0:417A

* 1080::34:0:417A

Helpful commands:

Display Connection Configuration: ipconfig /all

Display DNS Cache Info Configuration: ipconfig /displaydns

Clear DNS Cache: ipconfig /flushdns

Release All IP Address Connections: ipconfig /release

Renew All IP Address Connections: ipconfig /renew

Re-Register the DNS connections: ipconfig /registerdns

Change/Modify DHCP Class ID: ipconfig /setclassid

Network Connections: control netconnections

Network Setup Wizard: netsetup.cpl

Test Connectivity: ping www.whatismyip.com

Trace IP address Route: tracert

Displays the TCP/IP protocol sessions: netstat

Display Local Route: route

Display Resolved MAC Addresses: arp

Display Name of Computer Currently on: hostname

Display DHCP Class Information: ipconfig /showclassid

Green Apples Are Crisp

fivell — Thu, 07 Aug 2008 02:48:11 +0000

“Apple has been criticized by some environmental organizations for not being a leader in removing toxic chemicals from its new products, and for not aggressively or properly recycling its old products,” said Jobs. “Upon investigating Apple’s current practices and progress towards these goals, I was surprised to learn that in many cases Apple is ahead of, or will soon be ahead of, most of its competitors in these areas.”

“Fortunately, all iPod displays already use LEDs for illumination, and therefore contain no mercury,” wrote Jobs. “We plan to introduce our first Macs with LED backlight technology in 2007. Our ability to completely eliminate fluorescent lamps in all of our displays depends on how fast the LCD industry can transition to LED backlighting for larger displays.”

Enter: OLED

The first light-emitting polymer device involved a single layer of poly. Multilayer OLEDs can have more than two layers to improve device efficiency. As well as conductive properties, layers may be chosen to aid charge injection at electrodes by providing a more gradual electronic profile, or block a charge from reaching the opposite electrode and being wasted.

A voltage is applied across the OLED such that the anode is positive with respect to the cathode. This causes a current of electrons to flow through the device from cathode to anode. Thus, the cathode gives electrons to the emissive layer and the anode withdraws electrons from the conductive layer; in other words, the anode gives electron holes to the conductive layer.

Soon, the emissive layer becomes negatively charged, while the conductive layer becomes rich in positively charged holes. Electrostatic forces bring the electrons and the holes towards each other and they recombine. This happens closer to the emissive layer, because in organic semiconductors holes are more mobile than electrons (unlike in inorganic semiconductors). The recombination causes a drop in the energy levels of electrons, accompanied by an emission of radiation whose frequency is in the viable region. That is why this layer is called emissive.

Just like passive-matrix LCD versus active-matrix LCD, OLEDs can be categorized into passive-matrix and active-matrix displays. Active-matrix OLEDs (AMOLED) can make higher resolution and larger size displays possible. For a high resolution display like a TV, a TFT backplane is necessary to drive the pixels correctly.

OLEDs enable a greater range of colors, brightness, and viewing angle than LCDs, because OLED pixels directly emit light. OLED pixel colors appear correct and unshifted, even as the viewing angle approaches 90 degrees from normal. LCDs use a backlight and cannot show true black, while an “off” OLED element produces no light and consumes no power. Energy is also wasted in LCDs because they require polarizers which filter out about half of the light emitted by the backlight. Additionally, color filters in color LCDs filter out two-thirds of the light.

OLEDs also have a faster response time than standard LCD screens. Whereas a standard LCD currently has an average of 4-8 millisecond response time, an OLED can have less than 0.01ms response time.

The biggest technical problem for OLEDs is the limited lifetime of the organic materials. In particular, blue OLEDs historically have had a lifetime of around 14,000 hours (5 years at 8 hours a day) when used for flat-panel displays, which is lower than typical lifetime of LCD, LED or PDP technology—each currently rated for about 60,000 hours, depending on manufacturer and model. Toshiba and Panasonic have come up with a way to solve this problem with a new technology that can double the lifespan of OLED displays, pushing its expected life past that of LCD displays. A metal membrane helps deliver light from polymers in the substrate throughout the glass surface more efficiently than current OLED’s. The result is the same picture quality with half the brightness and a doubling of the screens expected life.

In 2007, experimental PLEDs were created which can sustain 400 cd/m² of luminance for over 198,000 hours for green OLEDs and 62,000 hours for blue OLEDs.

The intrusion of water into displays can damage or destroy the organic materials. Therefore, improved sealing processes are important for practical manufacturing and may limit the longevity of more flexible displays.

TextCache

fivell — Mon, 04 Aug 2008 23:20:17 +0000

A TextCache is a text file which contains key-string pairs. The keys are strings which have the keyLeader character as its first character. The string associated with a key is separated from the key by the keySeparator character. The default value for keyLeader is an ampersand ‘@’ and the default for the keySeparator is the equals sign ‘=’. Everything following the keySeparator up to the next keyLeader or the end of the text file is the text string. An exception is that blank characters at the end of a string element are removed and any new line character in the text file is replaced by a blank. The key-string pairs are cached in memory after instantiation and the strings my be retrieved by using the respective keys.

TraceRoute

fivell — Thu, 15 May 2008 01:24:40 +0000

Traceroute is often used for network troubleshooting. By showing a list of routers traversed, it allows the user to identify the path taken to reach a particular destination on the network. This can help identify routing problems that may block or slow access to a web site.In the early days of the Internet such detailed information about the path a packet took was considered acceptable and convenient. However, hackers have exploited this helpful tool in order to acquire sensitive information about a company’s network architecture. By using the traceroute command, a hacker or several hackers can quickly map a company’s network architecture and use that information to launch attacks.

In general traceroute and ping have the lowest priority of all packets. E-mail, web browsing, ftp, etc. data take precedence over traceroute data.

For example if a router is passing secure web data to a customer and another customer starts to ping that router. The router will put a ‘hold’ on the ping packets until it is ready. Because of situations like this, most traceroute programs send 3 different requests. Since one of the requests may be put on ‘hold’ due to higher priority data being sent, the program tests the path 3 times.

Over the past several years network devices have been electronically attacked via the use of ICMP. These attacks have proved to be very effective in the past, and in some situations they still are. Network device (routers, switches, etc) vendors have taken steps to lessen the impact of these attacks destined to their devices. They have done this by limiting the number of ping and traceroute messages received/processed per unit of time. In any given service providing network, multiple devices send/receive ping and traceroute messages on a perpetual basis. Add to this, the number of user/gamer/student/entrepreneurs who continuously run traceroute programs like ping plotter, and the ping and traceroute limits to the devices will be reached very quickly.

How to read traceroute data:

Let us do a traceroute to a site we know responds to ICMP packets.

Tracing route to cnn.com [64.236.16.20] over a maximum of 30 hops:

1 57 ms 28 ms 50 ms ip68-100-1-97.dc.dc.cox.net

2 341 ms 74 ms 156 ms ip68-100-0-1.dc.dc.cox.net [68.100.0.1]

3 28 ms 207 ms 52 ms mrfddsrj01gex070004.rd.dc.cox.net

4 * ms 274 ms 235 ms mrfdbbrj01-ge020.rd.dc.cox.net

5 73 ms 12 ms 84 ms mrfdbbrj02-ge030.rd.dc.cox.net

6 107 ms 38 ms 47 ms ashbbrj02-so000.r2.as.cox.net

7 35 ms 39 ms 54 ms ashbbbrj01-ae0.0.r2.as.cox.net

8 100 ms 38 ms 51 ms pop1-ash-S0-3-2.atdn.net

9 65 ms 40 ms 20 ms bb1-ash-P0-0.atdn.net [66.185.144.192]

10 40 ms 37 ms 51 ms bb2-vie-P11-0.atdn.net [66.185.152.101]

11 36 ms 35 ms 64 ms bb2-atm-P3-0.atdn.net [66.185.152.33]

12 51 ms 70 ms 45 ms bb2 [66.185.152.3]

Looking at this traceroute, one can see that roundtrip times to the site are very good (12 51 ms 70 ms 45

ms bb2 [66.185.152.3]) However looking at #4, one may determine that there is a problem at that device when there is not. When an actual problem occurs with a device that causes latency, that latency is carried on through the other hops.

If the router at #4 was causing latency to the connection at www.cnn.com, one would see increasing times at hop #5, #6, #7 and so on. Since all packets have to traverse the router at #4, any latency created by that device would carry on to the end of the traceroute.

Vendors sometimes limit the amount of ICMP packets that their equipment will respond to. This can produce confusing results. When reading a traceroute, look for latency (high return times) to carry though to the final destination.

Here is an example of a traceroute when there is a problem inside a network:

1 31 ms 27 ms 28 ms core1-loopback-0.Brisbane.netspace.net.au [203.17.101.6]

2 33 ms 30 ms 28 ms AS7496.brisbane.pipenetworks.com [218.100.0.20]

3 228 ms 329 ms 228 ms fa1-0-6.xr2.wic.server-web.com [203.147.255.118]

4 215 ms 232 ms 228 ms gi2-0.xr2.bne.server-web.com [203.147.255.237]

5 233 ms 229 ms 233 ms core.mls1.bne.server-web.com [203.147.255.246]

6 232 ms 232 ms 233 ms bne606d.server-web.com [202.139.232.71]

As one can see, between hop #2 and #3, the time jumps from 33 ms to 228 ms and the latency continues through to its final destination at #6.

Understanding Digital and High Definition Effects

fivell — Sun, 04 May 2008 07:13:53 +0000

Effects and explanations concerning digital/highdef televisions.

Silk Screen Effect, SSE

The Silk Screen Effect, often referred to as simply SSE, applies only to rear projection televisions such as DLP, LCD and LCoS. Some times, when viewing white or other very bright colored objects, you see what appears to be the texture of the screen itself in front of the image. This gives the appearance that you’re watching the content through a silk screen. Some also describe it as an unnatural shimmering or sparkling on those bright areas. It can be greatly reduced with proper calibration. Typically reducing brightness and contrast, and to some extend adjusting picture control, can nearly eliminate the issue.

Screen Door Effect, SDE

The next acronym on the list is SDE or Screen Door Effect. This applies to all digital, or fixed pixel, televisions including rear-projection, plasma and flat panel LCD. If you own one, feel free to investigate this for yourself. When you get close enough to the screen you can actually see gaps between the pixels, producing what appears to be a grid on the screen. From that vantage point, it appears as though you’re watching TV though a window screen or screen door. All digital televisions have this issue, but the larger the pixels the more pronounced the effect. For example the old EDTV (480p) plasmas were infamous for screen door effect, whereas you can only see it on newer 1080p units when you’re incredibly (uncomfortably) close to the screen. The only way to eliminate SDE is to move further away from the screen.

Rainbow Effect

Rainbows are a DLP only phenomenon, specifically single-chip DLP. They have mostly been eradicated in the newer models, especially the LED based units. Traditional, bulb-based DLP televisions use a rapidly spinning color wheel to put color on the screen. The traditional color wheel has red, blue and green segments, and the bulb illuminates the screen in color by shining enough light through each segment that it blends together to form the color you want to see on screen. As a result only one color is actually on the screen at any given time. It is possible for some people to see this formation occurring and perceive it as a rainbow of the three distinct colors. It usually happens when a bright image appears on a very dark background, and for some only happens when they pan their eyes across the screen. There is no way to reduce the effect in an existing television set. Manufacturers have eliminated it by using faster color wheels with more color segments. LED based DLP televisions refresh fast enough that the effect is all but eliminated.

Refresh Rate

A television’s refresh rate describes how often a new image can be displayed on screen. Unlike prior analog technologies (CRT) where the entire screen was redrawn periodically, the new digital TVs only need to update the pixels that have changed since the last time an image was displayed. So the refresh rate essentially describes how often the display will check to see if any pixels need to be updated. All HDTV technologies have a refresh rate that should match or exceed the maximum number of video frames that can be shown per second. As the name implies, it is a rate, witch mathematically is the inverse of time, so the larger number the better. A refresh rate of 120Hz is better than a refresh rate of 60Hz.

Frame Rate or Frames per Second, FPS

It is important to note the distinction between frame rate and refresh rate. Frame rate typically describes the video content a television will display. Again, the higher number the better because the more video frames you get per second, the smoother the motion appears on the display. So 60 fps is usually considered better than 30 fps, although film is typically shot in 24 fps, so preserving that original rate is often desirable. A screen must have a refresh rate that equals or exceeds the minimum fps you want to watch. Obviously if you’re trying to view 60 frames per second, but only refreshing the screen 30 times per second, you’ll only see every other frame. Similarly, if the refresh rate of the screen is not a even multiple of the frame rate, the display will need to do some complex math to determine how to show what frames and for how long. Otherwise some frames will appear for multiple refreshes and others will appear for only one. This causes really choppy motion on screen.

Response Time

Often confused with refresh rate, response time measures how quickly a display can update an individual pixel. As a measure of time in this case, the smaller number the better. We’d like for the response time to be instantaneous, or nearly 0. Technically, response time is how long it takes for an individual pixel to go from black to white and back to black again. LCD is the only technology that has ever really suffered from slow response times; Plasma has almost instant response and DLP is very fast as well. With slow response times it’s possible for images, or “shadows” of images to appear on screen longer than they should. This is often referred to as ghosting or smearing. In the early days of LCD TV, a 16 ms response time was deemed adequate for home video, but 12 was necessary for gaming. Most modern LCD TVs have a response time of 8ms or less, making it almost impossible for most people to see any ghosting.

In-Plane Switching, IPS

Along with slow response times, another known on early LCD televisions was their very narrow viewing angle. Off angle viewing was, let’s just say, less than ideal. The advent of in-plane switching solved that problem. The technology itself gets a little too involved to discuss on the show, but it’s important to know the LCD TVs with IPS have a practical viewing angle that rivals plasma. Early versions of IPS caused significant slowdown in response times, as high as 50ms. A newer version of IPS, called Super In-Plane Switching (S-IPS) offers all the benefit of IPS at the faster response times required by modern HDTV viewers.