Wednesday, November 19, 2008

Tech Info ASCII Table

Tech Info ASCII Table

Original Source ::http://www.zytrax.com/tech/codes.htm

Good old ASCII Table - we can never find one when we need it. Print it, stick it on YOUR wall and save OUR bandwidth!!

This apparently simple subject (a charcter code) turns out to be brutally complicated - well leastways to our modest brains. In the interests of sanity (ours) we have also produced a mercifully short character code overview.

ASCII is a 7-bit code (but encoded in an 8 bit octet) and is the US national implementation (ANSI X3.4-1986) of the IA5 character set defined in ITU-T T.50 - so there you go!

If you are into HTML encodings e.g. ©,™, € etc.. Remember if it is not in this table it is not ASCII - there are many other extended character coding systems. MS Word uses CP1252 (latin - 1) among others.

Char Hex Dec Name Char Hex Dec Name
NUL 00 0 Null @ 40 64 Commercial At
SOH 01 1 Start of Header A 41 65  
STX 02 2 Start of Text B 42 66  
ETX 03 3 End of Text C 43 67  
EOT 04 4 End of Transmission D 44 68  
ENQ 05 5 Enquire E 45 69  
ACK 06 6 Acknowledge F 46 70  
BEL 07 7 Bell G 47 71  
BS 08 8 Backspace H 48 72  
HT 09 9 Horizontal Tab I 49 73  
LF 0A 10 Line Feed J 4A 74  
VT 0B 11 Vertical Tab K 4B 75  
FF 0C 12 Form Feed L 4C 76  
CR 0D 13 Carriage Return M 4D 77  
SO 0E 14 Shift Out N 4E 78  
SI 0F 15 Shift In O 4F 79 Letter O
DLE 10 16 Data Link Escape P 50 80  
DC1 11 17 Device Control 1 Q 51 81 Letter Q
DC2 12 18 Device Control 2 R 52 82  
DC3 13 19 Device Control 3 S 53 83  
DC4 14 20 Device Control 4 T 54 84  
NAK 15 21 Negative Acknowledge U 55 85  
SYN 16 22 Synchronous Idle V 56 86  
ETB 17 23 End of Transmission block W 57 87  
CAN 18 24 Cancel X 58 88  
EM 19 25 End of Medium Y 59 89  
SUB 1A 26 Substitute Z 5A 90  
ESC 1B 27 Escape [ 5B 91 Open Square Bracket
FS 1C 28 File Separator \ 5C 92 Back slash
GS 1D 29 Group Separator ] 5D 93 Close Square Bracket
RS 1E 30 Record Separator ^ 5E 94 Circumflex/caret
US 1F 31 Unit Separator _ 5F 95 Underscore
SP 20 32 Space or Blank ' 60 96 Single Quote
! 21 33 Exclamation Point a 61 97  
" 22 34 Quotation Mark b 62 98  
# 23 35 Number sign (Pound sign) c 63 99  
$ 24 36 Dollar Sign d 64 100  
% 25 37 Percent Sign e 65 101  
& 26 38 Ampersand f 66 102  
' 27 39 Apostrophe (Single quote) g 67 103  
( 28 40 Opening Parenthesis h 68 104  
) 29 41 Closing Parenthesis i 69 105  
* 2A 42 Asterisk (Star sign) j 6A 106  
+ 2B 43 Plus Sign k 6B 107  
, 2C 44 Comma l 6C 108  
- 2D 45 Hyphen (Minus) m 6D 109  
. 2E 46 Dot (Period) n 6E 110  
/ 2F 47 Forward Slash o 6F 111 lower case o
0 30 48 Zero p 70 112  
1 31 49   q 71 113  
2 32 50   r 72 114  
3 33 51   s 73 115  
4 34 52   t 74 116  
5 35 53   u 75 117  
6 36 54   v 76 118  
7 37 55   w 77 119  
8 38 56   x 78 120  
9 39 57   y 79 121  
: 3A 58 Colon z 7A 122  
; 3B 59 Semi Colon { 7B 123 Open Curly Bracket
< 3C 60 Less Than | 7C 124 OR (Pipe)
= 3D 61 Equality } 7D 125 Close Curly Bracket
> 3E 62 Greater Than ~ 7E 126 Equivalence (tilde)
? 3F 63 Question Mark DEL 7F 127 Delete

USB and Firewire Pinout

Original Source::http://www.zytrax.com/tech/pc/serial.html

Tech Info - USB and Firewire

USB and FireWire (IEEE 1394a and b) represent the newer generations of external serial interfaces being adopted to reduce PC and connection costs and to improve performance.

USB (1.x and 2.0)

The USB specification defines A and B type connectors. A type connects to the host or a hub. Type B connects to the end peripheral. This is shown in diagram 1 below.

A new 'On-the-Go (OTG)' specification introduces a smaller (really) connector and peer-to-peer operation.

Great to see that the USB folk make their specs freely available unlike the IEEE 1394 folks.

USB System - Connector Types

Type A Pin assignment

USB Type A Female (Receptacle)
Pin Name Color Notes
1 VBUS Red Power
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground

Type B Pin assignment

USB Type A Female (Receptacle)
Pin Name Color Notes
1 VBUS Red Power
2 D- White Data -
3 D+ Green Data +
4 GND Black Ground

Mini-USB Type A/B Pin assignment

Defined as part of the 'On-the-Go (OTG)' enhancement, features a single connector type (A/B) and peer-to-peer operation.

Mini-USB Type A/B Female (Receptacle)
Pin Name Color Notes
1 VBUS Red Power
2 D- White Data -
3 D+ Green Data +
4 ID - Type A - GND: Type B - NC
5 GND Black Ground

IEEE 1394 (Firewire a.k.a. i.Link)

The IEEE high speed serial connector is known as Firewire and i.Link (Japan). The IEEE 1394a-1995 specification provides up to 400 M bit/sec and uses either a 6 pin connector (PCs/Computers) or a 4 pin connector (camcorders and AV equipment). The latest specification IEEE 1394b provides up to 800 M bit/sec (but is slated for 3.2 G bit/s) and uses a 9 pin connector which may operate in 'biligual mode' (will connect to either a 4 or 6 pin IEEE 1394a connectors but needs a special converter cable) or 'beta mode' (will connect to another IEEE 1394b system).

Firewire uses the Open Host Controller Interface (OHCI)

As always the lack of freely available specifications is just a pain - leading to confusion and plain stupidity. It is a shame that the IEEE 1394 working group could not take a leaf out of the IEEE 802 group which now provides specs at no cost 6 months after their initial publication. Sigh.

Firewire/i.Link 6 Pin Connector Assignment

This connector is usually found on PCs (Apple especially) and disk systems.

.
IEEE 1394a-2000 (Firewire) 6 Pin Female (Receptacle)
Pin Name Color Notes
1 Power - Power (18V - 25V, 15W)
2 GND - Ground
3 TPB- - Pair B -
4 TPB+ - Pair B +
5 TPA- - Pair A -
6 TPA+ - Pair A +

Firewire/i.Link 4 Pin Connector Assignment

This very compact connector is usually found on camcorders and other digital AV equipment.

IEEE 1394a-2000 (Firewire) 4 Pin Female (Receptacle)
Pin Name Color Notes
1 TPB- - Pair B -
2 TPB+ - Pair B +
3 TPA- - Pair A -
4 TPA+ - Pair A +

Firewire/i.Link 9 Pin Connector Assignment

This is the new IEEE 1394b (Firewire 800) connector which allows interconnection to older 1394a systems in 'bilingual mode'(4 or 6 pin - using an appropriate converter cable). In 'beta mode' allows connection to other 1394b systems.

Note: The power specification shown below (12 - 25V) highlights the problems of keeping definitive specifications limited to folks who are prepared to shell out filthy lucre for the privilege of reading the three lines that interest them and the confusion that arises as users legitimately try to reconcile various published specs and product notes. Various device specifications, notes and descriptions contain a variety of specific power values within the range shown below. The majority of chipset specifications use a low figure of 12V, many device descriptions (some based on the same chipsets) maintain the older maximum value of 25V. Since one of the benefits of the 1394b specification is longer cable runs on certain media types we have shown the low value as 12V since this seems to allow for increased voltage drop and consequently makes sense to us. We would be delighted to provide further information and clarification on this topic if anyone cares to update us.

IEEE 1394b (Firewire) 9 Pin Female (Receptacle)
Pin Name Color Notes
1 TPB- - Pair B -
2 TPB+ - Pair B +
3 TPA- - Pair A -
4 TPA+ - Pair A +
5 TPA(R) - Pair A Ground Ref.
6 VG - Power Ground
7 SC - Status Contact (Reserved NC)
8 VP - Power (12-25V DC, 15W)
9 TPB(R) - Pair B Ground Ref

Friday, November 14, 2008

Plasma vs. LCD

Plasma vs. LCD

Source: http://reviews.cnet.com/4351-12658_7-6583301.html
Having trouble discerning between plasma and LCD televisions? This handy chart can help you determine which technology is best for you.

  Plasma LCD
General
Screen sizes
42-65+ inches
5-65+ inches
Cabinet depth
3+ inches
3+ inches
Power consumption
Slightly less-efficient per square inch
Slightly more-efficient per square inch
Off-angle viewing
Excellent from all angles
Image fades slightly when seen from extreme angles from sides or from above or below
Reflectivity of screen
Glass screens can reflect lots of light, so may be an issue in very bright rooms. Some models have glare-reducing screens that are more- or less-effective
Matte plastic screens usually reflect less light. Some models have screens that are actually more reflective than plasma
Features
PC connectivity
Less common but still included on many models
More common than with plasma
Other features
Varies per model
Varies per model
Picture quality
Motion blur caused by display
Negligible
Difficult to discern on most models, although subject to more blurring than plasma. 120Hz models less-subject to motion blur
Black-level performance (depth of "black" displayed)
Varies, although excellent on many models.
Varies, although generally worse than plasma on many models, and better than plasma on best models
Color saturation
Varies, although generally a bit better than LCD due to black level and off-angle advantages
Varies, although the best models can equal the best plasmas
Resolution
Typically 720p, up to 1080p on high-end models. The benefits of 1080p are not obvious at screen sizes below 50 inches to the majority of viewers.
Typically 720p, but 1080p is more common than plasma at more price and size points. The benefits of 1080p are not obvious at screen sizes below 50 inches to the majority of viewers
Durability
Burn-in (faint after-images left on-screen)
Possible with still images left on-screen with very bright settings for hours, although new models much less susceptible, and most burn-in is temporary and goes away after watching moving images
May occur in extreme situations (very bright still images left on-screen for days) but much less likely than with plasma or even standard tube TVs.
Lifespan (hours until fades to half-brightness)
Typically 60,000 hours, or about 20 years if used 8 hours per day.
Typically 60,000 hours, or about 20 years if used 8 hours per day.
Program type
HDTV
Excellent
Excellent for HDTV-compatible models.
Standard-definition TV
Dependent mostly on screen size. The smaller the screen, the better standard-def usually looks
Dependent mostly on screen size. The smaller the screen, the better standard-def usually looks
DVD Movies
Excellent given a model with good black-level performance
Very good, although models with worse black-level performance are less desirable
Games
Excellent for most users, although burn-in might deter gamers who leave screens paused for hours or overnight
Excellent, although motion blur might deter the most sensitive gamers

Centos 7 reset root/ any user lost password / lockout due to cant remember password

1. Need to be in front of the terminal. (Physically if not vm). 2. Reboot the server 3. Press 'e' in the GRUB2 boot screen. 3. bunch...