Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
On Jul 21, 2011 9:23 AM, "Lisi" wrote: > > On Tuesday 19 July 2011 22:43:40 Alan Gauld wrote: > > Growing to hate my Netbook keyboard more by the day! > > Attach another keyboard? (To keep life simple it would have to be usb, but > you can even get a keyboard that will roll up for carrying. I have neither > seen nor tried one, so it may be no good!) > > Lisi Having used and owning the roll up kind, they're not very good. It's very similar to typing on a bad keyboard with the keys off. I bought a smaller keyboard for $10 on amazon that had full size keys and was quite nice, until the stress of sticking it in my backpack shorted the cord. That's what I'd recommend if you still want something portable, though it's easily the size of my wife's netbook. If you want a good keyboard, I'm addicted to mechanical switched keyboards, despite the price tag. -Wayne ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
Thanks a lot for your explanations, that was most helpful! I never realized my mother tongue (Dutch) is Little Endian, whereas English is Big Endian, e.g.: dutch: negen-en-twintig (nine-and-twenty) english: twenty-nine I will improve my program based on what you all have said. I will let the program: -find out the encoding of the input file -find out the encoding of the terminal -if necessary: find out if there are any other, compatible encodings on the terminal Thanks again! Cheers!! Albert-Jan ~~ All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? ~~ --- On Thu, 7/21/11, Steven D'Aprano wrote: From: Steven D'Aprano Subject: Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'? To: tutor@python.org Date: Thursday, July 21, 2011, 2:56 PM Dave Angel wrote: > Little-endian is the method used by the Intel processor (such as the > Pentium). Big-endian is the system used by most network protocols, as well > as the 68000 and many other processors. There used to be mainframes with various forms of middle-endian layouts. Fortunately they are no longer around. http://www.retrologic.com/jargon/M/middle-endian.html > For our purposes, it's the ordering of the bytes within a 16 or 32 bit > number. Little-endian puts the least significant byte first, while > big-endian puts the most significant byte first. In this context, least significant and most significant may need explaining. In decimal numbers, we write one hundred and twenty-three as 123. The 1 is most significant, because it represents 1 HUNDRED rather than 1 UNIT. And similarly the 3 is least significant. So numbers using Arabic numerals are big-endian. The same applies for computer integers. 123 written in hexadecimal is 7B, which of course is big-endian just like decimal. But when storing this number in memory, we have a choice: we can store it in big-endian format, just like we write it: 7B, where the 7 is the "left-most" (lowest address) number. Or we can store it in little-endian format, B7, where the 7 has the higher address, and read from right-to-left. And of course, bytes themselves can be either little-endian or big-endian, *independently* of byte ordering within larger units. http://en.wikipedia.org/wiki/Endianness http://en.wikipedia.org/wiki/Bit_numbering -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
>Attach another keyboard? (To keep life simple it would have to be usb, but >you can even get a keyboard that will roll up for carrying. I have neither >seen nor tried one, so it may be no good!) On the plus side, roll-up keyboards tend to be sealed and proof against liquids. Plus, they are usually fairly quiet. Ramit Ramit Prasad | JPMorgan Chase Investment Bank | Currencies Technology 712 Main Street | Houston, TX 77002 work phone: 713 - 216 - 5423 This communication is for informational purposes only. It is not intended as an offer or solicitation for the purchase or sale of any financial instrument or as an official confirmation of any transaction. All market prices, data and other information are not warranted as to completeness or accuracy and are subject to change without notice. Any comments or statements made herein do not necessarily reflect those of JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission may contain information that is privileged, confidential, legally privileged, and/or exempt from disclosure under applicable law. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or use of the information contained herein (including any reliance thereon) is STRICTLY PROHIBITED. Although this transmission and any attachments are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable, for any loss or damage arising in any way from its use. If you received this transmission in error, please immediately contact the sender and destroy the material in its entirety, whether in electronic or hard copy format. Thank you. Please refer to http://www.jpmorgan.com/pages/disclosures for disclosures relating to European legal entities. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
On Tuesday 19 July 2011 22:43:40 Alan Gauld wrote: > Growing to hate my Netbook keyboard more by the day! Attach another keyboard? (To keep life simple it would have to be usb, but you can even get a keyboard that will roll up for carrying. I have neither seen nor tried one, so it may be no good!) Lisi ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
Dave Angel wrote: Little-endian is the method used by the Intel processor (such as the Pentium). Big-endian is the system used by most network protocols, as well as the 68000 and many other processors. There used to be mainframes with various forms of middle-endian layouts. Fortunately they are no longer around. http://www.retrologic.com/jargon/M/middle-endian.html For our purposes, it's the ordering of the bytes within a 16 or 32 bit number. Little-endian puts the least significant byte first, while big-endian puts the most significant byte first. In this context, least significant and most significant may need explaining. In decimal numbers, we write one hundred and twenty-three as 123. The 1 is most significant, because it represents 1 HUNDRED rather than 1 UNIT. And similarly the 3 is least significant. So numbers using Arabic numerals are big-endian. The same applies for computer integers. 123 written in hexadecimal is 7B, which of course is big-endian just like decimal. But when storing this number in memory, we have a choice: we can store it in big-endian format, just like we write it: 7B, where the 7 is the "left-most" (lowest address) number. Or we can store it in little-endian format, B7, where the 7 has the higher address, and read from right-to-left. And of course, bytes themselves can be either little-endian or big-endian, *independently* of byte ordering within larger units. http://en.wikipedia.org/wiki/Endianness http://en.wikipedia.org/wiki/Bit_numbering -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] little/big endian was Re: what is 'doubleword alignment'?
On 07/19/2011 05:43 PM, Alan Gauld wrote: Albert-Jan Roskam wrote: > and ctypes to process the data in python. It works now, although I > still want to read more about this. Where does the distinction > little/big endian enter this story? That's to do with which bit in a byte/word is most significant. e.g. is the decimal value 1 stored as 0001 # the one on the right hand nibble or as 0001 # the one on the left hand nibble Now scale that up to word sized numbers... Different CPUs do it differently. I can't recall which is which - I'm sure wikipedia will reveal all! :-) Little-endian is the method used by the Intel processor (such as the Pentium). Big-endian is the system used by most network protocols, as well as the 68000 and many other processors. For our purposes, it's the ordering of the bytes within a 16 or 32 bit number. Little-endian puts the least significant byte first, while big-endian puts the most significant byte first. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] little/big endian was Re: what is 'doubleword alignment'?
Albert-Jan Roskam wrote: > and ctypes to process the data in python. It works now, although I > still want to read more about this. Where does the distinction > little/big endian enter this story? That's to do with which bit in a byte/word is most significant. e.g. is the decimal value 1 stored as 0001 # the one on the right hand nibble or as 0001 # the one on the left hand nibble Now scale that up to word sized numbers... Different CPUs do it differently. I can't recall which is which - I'm sure wikipedia will reveal all! :-) HTH, Alan G. Growing to hate my Netbook keyboard more by the day! And hating my PC repairer even more! ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
