Talk:Kansas City standard
- 1 Asynchronous serial communication, square wave
- 2 Lack of attribution problem???
- 3 1200 baud variation
- 4 BYTE's Audio Cassette Standards Symposium
- 5 1200/2400Hz: What an odd choice!
- 6 also used by sinclair?
- 7 Atari variation?
- 8 Sorcerer Exidy and Sega SC-3000
- 9 "Kansas City" standard vs Kansas City Standard
- 10 Altair 88-ACR (Audio Cassette Recorder) interface boards
- 11 Little endian
I presume "asynchronous" here means "in asynchronous start-stop serial format".
- Yes -- Egil 11:34 Mar 10, 2003 (UTC)
As I recall, most of the implementations generated the output in software as a square wave, which was then filtered before reaching the tape. Similarly, AFAIR the decoding was done using a hardware zero-crossing detector with hysteresis, and then post-processed in software to recover the data... Please let me know if I'm wrong about this.
Lack of attribution problem???
The text of this article sounds so much like http://www.alphalink.com.au/~edsa/#kcs, I'm inclined to think it came directly from there, with just enough changes to avoid being a copyvio. RoySmith 14:00, 20 July 2005 (UTC)
1200 baud variation
I don't know about Acorn Computer's 1200 baud version but Processor Technology had the 1200 version going in mid 1976. Lee Felsenstein was an author of the standard and a designer at Processor Technology.
I don't know what to do with UFE file format stuff. (Swtpc6800 23 February 2006)
It may not be appropriate to refer to Processor Technology's 1200 baud format as Kansas City Standard as it used different tones (600Hz and 1200Hz). PT did however record their tapes in both formats - 300 baud KCS on one side and 1200 baud CUTS on the other.
Add to the confusion is that PT appear to use the acronym CUTS for two different things: 'Computer Users Tape Standard' and 'Computer Users Tape System' - the former referring to their 1200 baud format; and the latter to their cassette interface unit (which supported both KCS and CUTS formats).
http://www.sol20.org/articles.html has a number of Processor Technology newsletters and adverts.
It is interesting to note that only in the UK was the term CUTS used synonymously with 300 baud KCS - most notably by ACORN and the Compukit UK101 makers. (Ed. 4 November 2006)
I wrote some DSP code to read BBC-B (ACORN) tapes via a soundcard... And I'm certain that it was 1200 baud modulated C/W onto the 1200Hz carrier. The UART strobes were kept in sync with the carrier generator. During playback a phase locked loop was used to maintain the carrier sync while reading a zero. ISTR that earlier machines used a different format, which might have been KCS. The format used by the BBC-B is described in after market editions of the Users guide, and the tape interface ASIC was described in the Advanced Reference Manual. (I'll get you references for this next time I raid my loft!) 126.96.36.199 16:37, 2 September 2007 (UTC)
BYTE's Audio Cassette Standards Symposium
Manfred and Virgina Peschke - BYTE Magazine, Feb 1976, Pages 72 and 73
-- SWTPC6800 03:24, 9 August 2007 (UTC)
1200/2400Hz: What an odd choice!
Never being aware of the technicalities of this standard before, I am quite surprised that 1200/2400 Hz tones are used. While generating them is obviously extremely simple, this choice suffers from a very obvious drawback, in that distorted playback will tend to cause the 1200Hz to be decoded as 2400Hz - the second harmonic. Distinguishing the tones then becomes very difficult and error prone. No doubt square waves were also used in the encoder part, followed by a crude analogue filter. This makes the problem potentially even worse. Is there any evidence to support this poor performance prediction? A better choice would have been to use harmonically unrelated tones as in selective calling systems, though this would have added complexity. A compromise might have been to use 1200/1800Hz in a 1:1.5 cycle ratio, as in FFSK signalling systems. These are very noise and distortion proof, yet easy to generate. Graham 13:02, 8 March 2006 (UTC)
My theory is that the participants in the symposium were not signal engineers, but ranged from computer "enthusiasts" to people who work with digital computers, so they did not have the experience or knowledge to understand that issue. -Luciuskwok 04:08, 29 May 2006 (UTC)
Your observation about the harmonics is not new. I read about it when people were still using Kansas City Standard tapes. The author said something to the effect of "if there had been any analog engineers at the meeting, then ..." Unfortunately, I can't give you a citation, but I would think probably Byte before 1980. 188.8.131.52 (talk) 19:59, 7 October 2011 (UTC)
also used by sinclair?
at one, more geekier time, i did a little bit of audio analysis on a bit of spectrum-sounding noise included in a certain piece of cult pop music (reminiscing on memories of that very computer)... though i can't remember the frequencies involved, the oscilloscope-style waveform certainly looked a lot like what i'd expect KCS to. (even managed to decode what it said, thru bits into ascii bytes). can't see it attributed here - was it KCS that sinclair used (for the zx80, 81, spectrum, etc)?
certainly the loading times would suggest such - even a BASIC listing of a couple hundred lines, or a 16k commercial program took a couple of minutes, a 48k one would allow you time to make a cup of tea, and a 128k time enough to cook lunch and eat it too... plus the infamous R: TAPE LOADING ERROR whenever the rather fragile codec suffered a dropout (or harmonic distortion, etc) somewhere along the line.
>> ANSWER from amonymous.. no, all the micros analouge tape storage used to generate squqare waves, but the encoding was quite different. The ZX81 and ZX80 in particular had a very weak encoding based on a single tone. —Preceding unsigned comment added by 184.108.40.206 (talk) 06:57, 23 May 2011 (UTC)
I know Atari 800 (and later, esp. 65 XL/XE series, I own a few) used AFSK to encode data on audio tapes. The data bit was lead by one start bit, and one stop bit, making it a total od 10 bits per byte. The frequencies are a little different, though - mark tone at 5327 Hz, space tone at 3995 Hz (or close). The effective standard baud rate was 600 (but POKEY could accept it even if it went as high as 820, sometimes more). The data was written in series of bytes separated by carrier tone.
I don't know what kind of 'standard' that is, though. The Atari machine, when instructed to save data to tape, did record its data in one format only, true - but original games came pre-recorder from the manufacturer, and sometimes the recording technique was somewhat different (for example, considerably longer data segments).
Sorcerer Exidy and Sega SC-3000
The Sorcerer Exidy (earlier computer) should be compatible to the KCS, at least at 300bps but at 1200 baud mode, which was the default one, worked at half of the frequency with a single 'period' for 'one' and only half period for 'zero', which had an obvious impact on the phase. The data stream was divided in 256 (+1 for checksum) bytes chuncks but the 16 (+checksum) bytes header, with the interposition of 101 leading bytes between the blocks.
The Sega SC-3000 BASIC had a custom variation (half of the number of "waves" compared to the 300 bps KCS mode) to run at 600 baud.
In both the cases the data bytes where identified by a zeroed bit for start and two stop bits set to 'one', as for the standard. —Preceding unsigned comment added by 220.127.116.11 (talk) 08:23, 23 May 2011 (UTC)
"Kansas City" standard vs Kansas City Standard
Southwest Technical Products Corp was the most significant home computer maker to use the standard developed in Kansas City with their AC-30 Cassette Interface. Their advertisement referred to this as the "Kansas City" standard. (With quotes around Kansas City.) Harold Mauch was the primary author of the standard and his company, Percom Data, used the term Kansas City Standard. I will upload some of the ads to the Commons in the next few days.
- If you can provide better details, this would be most welcome. Regarding the name, I've seen all of them:
- "Kansas City" standard
- Kansas City Standard
- Kansas City standard
- We should use the "official" spelling, if there is any. If not, we should use the common spelling used by the majority of participants at its time. --Matthiaspaul (talk) 11:06, 29 January 2012 (UTC)
- Let's be clear: there is no spelling issue, just a styling issue. If there was an official or common standard styling, it wouldn't be an issue; but there's not, so we should go by the stlying recommended in WP:MOS and WP:TITLEFORMAT: lower-case, no quotation marks, Kansas City standard; this is among the styles common in sources, so should be no issue. Dicklyon (talk) 19:53, 29 January 2012 (UTC)
- I'm looking forward to Michael's uploads and think they may be helpful in resolving the issue. I also think updating the article itself with further details on the development and history of usage of the KCS will perhaps help us settle on the best title. We should probably use both "Kansas City" standard and Kansas City Standard in the article text, but of course there can only be one title.
- I'm not sure that the guidelines at WP:TITLE and WP:OFFICIALNAMES are going to give us a clear cut answer, and consistent with usage in reliable English-language sources isn't helpful when the sources are so split in their usage. The applicable guideline I see is Use lower case, except for proper names, which leaves us to determine whether Kansas City Standard is a proper name or not. The article Technical standard discusses the types of standards: there is a spectrum running from specifications, which are often if not always capitalized, to de facto standards, which probably shouldn't be capitalized, but in practice we often see text like Capitalized Proper Product Name became a de facto standard. KCS seems to be in a grey area of the spectrum. Seems we had one official KC capital-Standard, which was not widely implemented because it was too slow. Then there were several other products with technical improvements that, by convention, seem to fall into a KC lowercase-standard family of related products. If the article discusses the wide spectrum of products, then we could keep the current name, as it seems the common naming convention for the term S-100 era cassette tape standards (plural) Wbm1058 (talk) 21:58, 29 January 2012 (UTC)
- Probably the most clear-cut guidance is the lead at MOS:CAPS. I don't think there was more than one Kansas City standard. Dicklyon (talk) 22:17, 29 January 2012 (UTC)
- Wikipedia avoids unnecessary capitalization. Most capitalization is for proper names, acronyms, and initialisms. Wikipedia relies on sources to determine what is a proper noun; words and phrases that are consistently capitalized in sources are treated as proper nouns and capitalized in Wikipedia.
- I don't see consistent lack of capitalization in reliable sources. We may just have to respectfully disagree on that. I see there are already at least 3 standards mentioned in the article, and there may be more: (1) The original 300 baud standard (2) CUTS (Computer Users' Tape Standard) (3) Acorn Computers Ltd implemented a 1200 baud variation of CUTS (4) Tarbell Cassette Interface ? Wbm1058 (talk) 22:36, 29 January 2012 (UTC)
Discussion moved from personal talk page
This issue arose from my move of Kansas City standard to Kansas City Standard, mistakenly believing the issue was not controversial. Below is initial discussion on the topic, moved from my talk page Wbm1058 (talk) 20:37, 29 January 2012 (UTC)
Kansas City standard
W, many reliable sources, possibly most, use lower case for this unofficial standard; see books. I undid the move and one of your edits, but you should consider reversing the rest. Or start an RM if you feel strongly about capitalizing it. Dicklyon (talk) 01:41, 29 January 2012 (UTC)
- Hi! That link's interesting, I hadn't thought of including "cassette" in my search, just "Kansas City Standard" was returning a lot more hits to surf through! Anyhow, your link has 16 hits, and the results are an 8–8 tie between Kansas City Standard and Kansas City standard! I suppose if we just left a similar mixed set of links on Wikipedia, we would be mirroring the real world. I'm wondering what the "right" answer is by proper English grammar rules. I think if we're just considering some generic standard, it's lower case. But if we want to put a stamp of Official Authority on it, then we call it the Industry Standard Standard and make sure that all of our Very Official Organization's official standards are Capitalized. But here we have something put together by some people who weren't even sure they wanted to attend, and a standard that seemingly wasn't well adhered to. See InfoWorld: What happened to ill-fated Kansas City Standard? Note they capitalized it anyway. I think I saw another article that perhaps better portrayed it, "the so-called "Kansas City" standard" (lower case, with quotes around the city where they met. So I'm not sure what to do. Look at Category:Computer standards. We have Filesystem Hierarchy Standard, Legal Electronic Data Exchange Standard, HMG Infosec Standard (No.1), Trusted Computer System Evaluation Criteria (capital C Criteria), Pronunciation Lexicon Specification (Specification a near-synonym for Standard), and more. There is no consensus for KC on Wikipedia. Sorry, I didn't realize the split was so close and should have put it up for discussion. Some editors had it piped even!—Kansas City Standard—linking to lowercase while showing readers uppercase. So do we give the standard respect (bio. of living standards policy, heh) by capitalizing it? Or maybe I'm totally missing the grammar logic that should be used to make the decision? Wbm1058 (talk) 03:19, 29 January 2012 (UTC)
- Styles vary. WP style, per MOS:CAPS, is to avoid unnecessary capitalization, not to "mirror the real world" with all its random variability. Partly that's to avoid the false pretense of official authority, which is what does cause capitalization in some other styles. The Filesystem Hierarchy Standard, on the other hand, is consistently capitalized in sources, so we can reasonably infer that that's how it needs to be. That doesn't mean all decisions are right, or easy, which is why we still discuss and move back and forth, and so on; but we try. Dicklyon (talk) 05:10, 29 January 2012 (UTC)
Here are 4 advertisements for Kansas City standard cassette interfaces.
- File:SWTPC AC30 Cassette Interface July 1976.jpg
- File:PerCom CI 810 Cassette Interface Sep 1976.jpg
- File:PerCom CIS 30 Cassette Interface May 1977.jpg
- File:PerCom Cassette Interface Dec 1977.jpg
- Carl Helmers, the editor of Byte magazine, always used Kansas City standard. Here on page 10 in the December 1976 Byte . In the May 1977 issue he writes "the new Motorola evaluation board style computer, which comes in kit form with a new version of their monitor programs, a Kansas City standard tape interface…"
- I think that Kansas City standard is the best choice. -- SWTPC6800 (talk) 01:13, 30 January 2012 (UTC)
- Right. The editor of the magazine that sponsored the KC conference, and published the results, consistently called it "Kansas City" standard. You can't get any more official than that. Wikipedia guidelines say drop the quotes, so we have Kansas City standard. I now agree that is best, hopefully the matter is settled. Now the issue is, how many of those links I "fixed" should never have been linking here in the first place? An InfoWorld Aug 16, 1982 hardware review of the Radio Shack Color Computer says that the cassette deck records and plays back at 1500 baud, which is five times the speed of the "Infamous Kansas City Standard" and three times faster than TRS-80 Model I cassette system. I don't think the IBM PC would have still been using KCS. In fact, I'll guess that KCS' lifespan was only a couple years or so. Problem is, all these other home PCs with cassettes have no where else to link to say what standard they used, if not Commodore Datassette. It's not like there's an Industry Standard Architecture equivalent for cassette tapes. Wbm1058 (talk) 04:16, 30 January 2012 (UTC)
- I think that Kansas City standard is the best choice. -- SWTPC6800 (talk) 01:13, 30 January 2012 (UTC)
Altair 88-ACR (Audio Cassette Recorder) interface boards
This device appears to have been introduced about June 1975, predating the Kansas City meeting. Is it the first ever microcomputer cassette tape interface? How did it differ from KCS? Did KCS improve on it? Wbm1058 (talk) 00:09, 30 January 2012 (UTC)
- A small number of hobbyists were building computers before the Altair was announced in January 1975. The Mark-8 had a following in 1974. Don Tarbell had a working computer with cassette storage before 1975. He converted his design to work with the Altair, see Tarbell Cassette Interface. The Kansas City standard article is flawed because most of the computer listed there did not use the Kansas City standard data format. -- SWTPC6800 (talk) 01:25, 30 January 2012 (UTC)
The article says: “A word, usually one byte (8 bits) in length, was recorded in little endian order”. To me, little endian is a byte ordering scheme, not a bit ordering scheme. Although calling the less-significant-bit-first order “little endian” would be logical, that’s not what the term is usually used for. There seems to be ne specific term for this scheme. Any comments before I correct this? Palpalpalpal (talk) 20:33, 23 June 2012 (UTC)