OT: just a suggestion

Page 7 of 8  
On Sun, 27 Dec 2015 18:49:36 -0500, "J. Clarke"

it was stored ---
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 20:11:57 -0500, snipped-for-privacy@snyder.on.ca wrote:

Ah, the ol' Write-Only Memory! ;-)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

and the "one way backup" problem in Windows 2-3 period.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 17:03:20 -0500, clare wrote:

Close, but no cigar. My 8" drives were 1.2mb and were faster than the 5.25" because they stored more data on a "cylinder" so the head didn't have to be stepped as often. Also, they had a higher transfer rate.
That's not to say that a good software type couldn't fudge a little on all 3 types :-).
--
Nobody expects the Spanish Inquisition!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 28 Dec 2015 00:19:02 +0000 (UTC), Trenbidia

the capacity just went up and up - as did the data rate.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Puckdropper <puckdropper(at)yahoo(dot)com> wrote:

The 1541 was too rich for my blood back then, I was stuck with the slower, less expensive, but very reliable 1530 Datasette!
http://bit.ly/1OnkPv0
I still remember spending many hours typing in page upon page of raw machine language from 'Compute!'s Gazette' magazine and saving it to the 1530.
http://bit.ly/1Prhv7m https://en.wikipedia.org/wiki/Compute !'s_Gazette#/media/File:ComputesGazetteProgramPage.jpg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27 Dec 2015 14:52:45 GMT, Puckdropper <puckdropper(at)yahoo(dot)com> wrote:

that used (basically) an audio cassette type tape for digital data backup. Everything up untill the advent of DAT was basically an analog (audio) tape system using modem technology to put the digital data on the tape using analog technology.
When the moved to helical scan technology the lines started to blurr a bit more and the data became more digital in it's actual storage - similar to magneto-resistive recording on "magneto optical drives" and die sublimation on optical drives. - which were getting awfully close to the digital technology used for CD ROM and DVD in that there was no "modulation" used any more.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Leon wrote:

store the 0s and 1s, is not the issue.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
says...

So if I speak into a microphone "one, zero, one, one, zero ..." then it's "digital"?

And yet a cassette recorder has no trouble storing computer files.
Some signalling systems, the various Ethernets for example, are designed from the ground up to carry digital information. Others, POTS modems for example, carry digital information over channels that were originally intended to carry analog data and do so by modulating a carrier signal that is compatible with that channel.
That's where the distinction lies.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 04:37:11 -0500, "J. Clarke"

It is if you are transmitting binary code. Your baud rate would be abyssimal though!!!!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 04:37:11 -0500, "J. Clarke"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

computer systems like the RadioShack COCO (Color Computer) were digital data stored on an analog medium. There were only 2 tones recorded on the tape. If the frequency was between 2 levels it was a 1, and between two other totally different frequencies, it was a 0. Just like RS232, 2 voltage ranges -3 to -25 and +3 to +25 - anything between -3 and +3 was "noise"
A high quality tape duplicator could duplicate the digital tapes reliably, but trying to do it with a "dubbing" deck was pretty much destined to fail. When we had the "coco club" we would get programs published in "hot coco" magazine, and one member would key the program into his computer and save it to a cassette tape, then I would run off the tape on the duplicator so each member got a copy. I used a TELEX Copyette 4 head duplicator that we also used to make copies of sermon tapes at church for shut-ins who could not get to church.
(now it's all recorded digitally and put on the church website)
There was no ambiguity. So it was (binary) digital data. Any music or voice or other non-binary data on a cassette tape is analog.
Then of course, there is DAT (Digital Audio Tape) but that's a different subject.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

the computer (unless you changed subject in the middle of the paragraph and are talking about audio cassettes).
Yes, there are end-cases that are clearly one or the other. Most of what we deal with, these days, is not so clear. The distinctions are mostly just jargon or marketeering, with no real meaning.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
krw wrote:

not does not depend on the "carrier". For instance, a drawing is not digital. It could be digitized, in many different ways...
Bill
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

you don't know what information is being transmitted over it?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

and demodulates (MODulatorDEModulator) the signal at each end. Modulation is the hallmark of an alalog signal.(modulation also described, as I did in my "simplified" reply as varying frequency and intensity.
A digital signal does not use a "modem" It uses a "codec" (coder decoder) which converts a binary chain of data to "tokens" and transmits those "tokens" digitally across the network, and then at the other end "decodes" the "tokens" to a digital binary data stream again. All computers today are "digital devices", working with and understanding ONLY binary digital data.
JPEG, MP3, MP4, GIF, TIFF etc are all compression algorithms that define what tokens are used and how to code and decode the binary data for transmission.
The errors and retries in digital communications are the result of the "error correcting" or "error checking" built into the communication protocol - if a token arrives damaged, it is rejected and a resend is requested.
In analog communication there is no way to error check and error correct, so instead of getting data interruption you get data corruption - instead of getting pixellation and "digital dropout" you get "snow" "hiss" and other forms of "corruption" in the signal.
In Digital communications you get latency and dropouts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 16:20:27 -0500, snipped-for-privacy@snyder.on.ca wrote:

The "modulator" was a D/A converter and the demodulator was an A/D converter and it was analog in the middle, so the phone line is analog. How is the communications link digital?

A distinction without a difference. So you're saying that a v.90 modem is analog? DSL is analog? Cable Internet is analog?
There is no practical difference between a "token" and a "symbol". ("Baud" is defined as a symbol per second).

No, they are not for transmission, rather they are standardized encodings of objects (video, pictures, etc.). Transmission is only one use for such things (I bet you save some on your computer, even).

So? Internet over a 300bps modem can't have error checking, correction, or retries?

Really? I guess analog communications never existed (see above).

...and you don't in analog communications?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No, a "modulator" is not a DA converter, and nobody ever said "modem" communication was digital.

Nope. V90 is straight analog. DSL? I'm not sure. By my definition, since it uses a Modem, the transmission is a modulated signal - which means it is an analog signal. The cable internet uses DOCSIS and QAM, which is technically a CODEC, not a simple MODEM. QAM is quadrature amplitude modulation - which is a 4 state "digital" implementation instead of a binary digital - and ises "tokens" or "symbols" for upstream QAM, but uses MPEG for downstream.
Thats as much as I know about HOW it works - and it's different in north america (6mhz) DOCSIS and 8mhz EuroDOCSIS. - and the fiber optic backhaul works differently than the coax "last mile" section. Cable internet is digital - at least mine is. There is no modem. It runs with a digital router.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 27 Dec 2015 19:08:28 -0500, snipped-for-privacy@snyder.on.ca wrote:

OK, there is a DSP running the ADC. The second phrase is exactly the discussion here.

Agreed WRT v.90. Since DSL is *very* similar, I'd say so too but we're definitely in the minority.

Well, QAM can be more than four state. Forty years ago, we used 9600bps, 1200baud QAM modems (and Motorola called them "modems"), over dedicated copper phone lines. That's a three-bit (eight state) symbol.
MPEG isn't a transmission protocol, rather a compression algorithm.

It may be inside your house but it's using "TV channels" on the pole.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

strictly analog world. Docsis is also digital by definition.
ALL TV in Canada is now also digital - whether OTA or cable. Hook up an analog TV set to any Canadian cable system and just TRY to find a station you can view. They don't exist - You neet an ATSC tuner or a digital conversion box.
Try to get a station on an antenna with an NTSC tuner - you won't get any - they don't exist anymore. ALL digital (atsc) - so just because it uses a "tv channel" definitely does not preclude it being digital.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.