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Any reason to still want an 850?


ACML

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I know it was a great device back in the day, but why do I still want one? I know its a good solution for hooking up a parallel printer and serial modem, but I don't think that's something I plan to do anytime soon. My problem is that I still want one. Besides printers and modems, what is a current day use for an 850 (besides a door stop)?

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I've seen threads on here about Lantronics, but what does it do? There are no browsers to get on the web or are you talking about FTP sites on the web for strictly file transfer? I'm curious.

The main use would be to telnet to (or start running) a bbs system. That's what I run SFHQ on and there are quite a few others. You can do the same with APE and other solutions but I like the idea of the BBS operating without having to have a PC handle the communications. Works just as well with the 8-bits as well.

 

Then again, I hate to point out the obvious but... if you want one, get one! Don't overthink it. Let it be a doorstop then! As long as your kids aren't going to be missing any meals because you had to have one, who cares? What's the harm? Go for it. That's what collecting is all about. You don't see stamp collectors using their collections to mail out the electric bill payment, so go for it!

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I have one. I have it hooked up to a serial to ethernet adapter at the moment. I use it mostly for telnet-style applications emulating a modem. I could theoretically use it to do raw connections and have the Atari do the application protocol lifting if I was bored for things like FTP, etc.

 

I occasionally use it with a null-modem connection to a UNIX box. I have a real modem as well but it's not wired up because I don't have a landline anymore.

 

Basically, anything RS232 or a parallel port are useful for. Talking to things and printing. I use it to program routers with a serial console port once in a while.

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I know it was a great device back in the day, but why do I still want one?

 

Actually, even back then this device had a serious flaw, namely that you could not use the serial interface concurrently with the disk drive. Actually, that's pretty much a limitation of the SIO bus - or the lack of intelligence in the 850.

 

The reason why it is still useful today is for transfering data to and from the PC, with appropriate modem software on both sides. I used it to transfer my entire collection. Serial ports can still be found on some PCs, but parallel printers are really an extinct species.

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  • 3 months later...

so what software have you used to connect to a telnet bbs. Ive had no luck with bob term and tcpser

Haven't done it in a while, so I don't remember the version that worked best for me(I had trouble with one of the versions) - but bobterm works great for connecting to a telnet bbs.

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Since my post above, I ended up buying a couple of toys to play with. Kind of fits with my nag about copper is money. :)

 

So if you want to take a look at a dirt cheap WiFi adapter and some instructions on using it, follow this link.

 

http://www.instructables.com/id/Using-the-ESP8266-module/step1/Obtaining-and-preparing-your-8266-module/

 

I could be way off base here, I think this is the way forward. I'm so distracted with family stuff I've hardly had time in the last year to solder stuff.

 

That being said, I have three cellphones that act as WiFi hot spots, it was only a $5/month option so I got it on three. This isn't counting my other WiFi junk, just how low the entry is for a WiFi hot spot. If you already have a WiFi network, no additional cost.

 

I've also been reading up on the ESP8266 modules. Pretty much a stand alone processor with WiFi that handles all the negotiations. IOW: Instead of writing things like 'PING' on the Atari side, you just issue a PING request to the module. There would still be a number of things that have to be taken care of like a static IP, but there are several outfits that maintain your current address, whatever it may be or become, and direct traffic accordingly. The modules themselves are less then $5.

 

The only gotcha is the modules are 3.3 V. I stared at that for a while, thinking I would use something like a 4049 CMOS hex inverting buffer with 3.3 V regulator and the MPP handler to just hang it off a joystick port. After a while I thought it would actually be useful to hook it to something quicker then 300 BAUD so I came up with something equally as retro. What should be done is a 1489 with a 3.3 V supply doing the level translation and inversion. That scheme would open it up to anyone with a joystick port, which I dare to say is most people here as well as people with Black Boxes and PR:Connections to higher speeds.

 

So it kind of appeals to our demographic. [regulator, ESP8266, 1489] ~$6 for people that want to build it themselves, cheap and simple enough that you wouldn't get gouged too bad by the people that like building this kind of stuff to cover their Atari habit. Last time I looked, Lantronic was around $100 w/o cables.

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Actually, even back then this device had a serious flaw, namely that you could not use the serial interface concurrently with the disk drive. Actually, that's pretty much a limitation of the SIO bus - or the lack of intelligence in the 850.

 

The 850 is probably one of the most intelligent devices in the Atari 8bit series. The Atari 850 is less or more a computer by itself.

It does do concurrent I/O. Why would it otherwise be possible to run a BBS with it. If you mean with concurrent I/O that it transferred data realtime reading from diskdrive to rs232, yes you are right, but for the user this is almost not noticeable. You simply can use diskdrive and rs232 together. The driver inside the Atari 850 (downloaded by the Atari computer itself) takes care of all that.

 

You might be confusing the RVERTER with the Atari 850. The RVERTER was not able to do concurrent I/O, since that was just a simple Nullmodem device (actually the RVERTER almost a Sio2PC)

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The 850 is probably one of the most intelligent devices in the Atari 8bit series. The Atari 850 is less or more a computer by itself.

It does do concurrent I/O. Why would it otherwise be possible to run a BBS with it. If you mean with concurrent I/O that it transferred data realtime reading from diskdrive to rs232, yes you are right, but for the user this is almost not noticeable. You simply can use diskdrive and rs232 together. The driver inside the Atari 850 (downloaded by the Atari computer itself) takes care of all that.

 

You might be confusing the RVERTER with the Atari 850. The RVERTER was not able to do concurrent I/O, since that was just a simple Nullmodem device (actually the RVERTER almost a Sio2PC)

 

The 850 is a computer very much in the same vain as the 1050 is a computer, no difference. Yet, SIO does not support concurrent disk and RS232-IO. It supports a "small block mode" where you can write data out to the 850 which is buffered there, and once the buffer is full, data is written out to the RS232 interface. Reading from the serial input concurrently with disk operations is just not possible. If you wanted to do that, you first have to halt the serial transfer (for example by either sending an XOFF or by RTS/CTS), then write or read data to disk, then enabling serial transfer again. Yuck!

 

In its "concurrent" mode, i.e. the only mode where you can read or write to the RS-232 at the same time, the 850 has no "intelligence" at all. It only samples the serial line of pokey, and mirrors the levels exactly as they come in on the external connector. It does not interpret or buffer the data in any way. This is also the limitation for the 9600 baud: The 6507 that sits in the device cannot handle any faster transfer for mirroring the bits one by one.

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The 850 is a computer very much in the same vain as the 1050 is a computer, no difference. Yet, SIO does not support concurrent disk and RS232-IO. It supports a "small block mode" where you can write data out to the 850 which is buffered there, and once the buffer is full, data is written out to the RS232 interface. Reading from the serial input concurrently with disk operations is just not possible. If you wanted to do that, you first have to halt the serial transfer (for example by either sending an XOFF or by RTS/CTS), then write or read data to disk, then enabling serial transfer again. Yuck!

 

In its "concurrent" mode, i.e. the only mode where you can read or write to the RS-232 at the same time, the 850 has no "intelligence" at all. It only samples the serial line of pokey, and mirrors the levels exactly as they come in on the external connector. It does not interpret or buffer the data in any way. This is also the limitation for the 9600 baud: The 6507 that sits in the device cannot handle any faster transfer for mirroring the bits one by one.

 

You wrote in your first post about this subject that it is a real downside, which people back then also were suffering from. That is absolutely untrue. In daytime, regular use you never suffer from this downside at all, since it is not really a downside within the atari 8bit specs. You statet that the 850 does not do concurrent I/O which people unknown to this subject could explain like you can't use Atari 850 and diskdrives together, which isn't true.

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You wrote in your first post about this subject that it is a real downside, which people back then also were suffering from. That is absolutely untrue. In daytime, regular use you never suffer from this downside at all, since it is not really a downside within the atari 8bit specs. You statet that the 850 does not do concurrent I/O which people unknown to this subject could explain like you can't use Atari 850 and diskdrives together, which isn't true.

Actually, it is a really downside. You cannot use the 850 and the disk drive concurrently. Consider a situation where a modem is pushing data into the Atari. The time the Atari needs to empty its input buffer by writing data to the disk, it needs to hold serial communication. Incoming serial data during that time cannot be held within the 850, it is just lost. So you need some additional synchronization with the external source. Given that this synchronization also takes a while to arrive at the source of the transmission, namely the "hold on, I need to write data to the disk", another byte could already be on the line, and this byte would be lost.

 

Thus, for any type of file transfer, you need another type of protocol "on top" which requires the sender to pause the transmission after a "buffer full" of data. Sure, xmodem and friends do such tricks, but it is an anoyance that is due to a poor definition of the 850 interface protocol.

 

What Atari *should* have done instead is to buffer the data in the 850, do automatic hardware handshaking within the 850 itself (and not ping-pong via POKEY and the host), and transmit the data between the 850 and the main system using the SIO protocol. Note that this is not what is currently happening: Whenever you enter the "concurrent mode", the SIO protocol is bypassed and the data arrives in "raw form" on the SIO lines, and requires POKEY to synchronize to it, with the baud rate of the incoming data, not with the 19200 baud rate that is specified for SIO.

 

So yes, it *is* a poor design that was really driven by the cost factor. Additional buffering within the 850 would have required RAM there, i.e. more RAM than is currently in there. I believe the total ram amounts for something like 128 bytes in one of the RIOTs, which is used for the printer buffer, the small-block serial buffer, the stack and some temporaries.

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Some anecdotal data. :) Yes, the way Atari did it worked but I lean towards thorfdbg's peeves. You would occasionally run into the BBS that would have timing loops in its file download section. I specifically remember HomePak would take so long to write suspend the modem, write buffer out to drive, get back to xmodem download, that some BBSs would time out and abort the d/l. It was one of the main reasons someone wrote a hack to allow HomePak to use a ramdisk.

 

It was one of the reasons everyone would report buffer length in their telecommunication programs, one of the reasons it was important to have a ram disk, one of the reasons why high speed serial drives were important, and why devices like the Black Box and MIO were so popular. You were essentially downloading to your computer followed by downloading to your drive which was a relatively slow process: Turns your 19k connection into 9.6k throughput.

 

I was so annoyed by it at the time I even wire wrapped a 6551 into my memory map. Figure some of the complicated spaghetti code with few REMs and short variable names were just to get the buffer as big as possible. If it had been done like a lot of other hardware, you could have literally used zero bytes for buffer and GET/PUT from drive to modem or modem to drive or modem to printer.

 

Things kind of worked out because of the problem of course. Specifically people that were running things like BBSs created a market for parallel fast devices like the MIO and Black Box. There's a chance we would not have seen some pretty good programs and hardware if Atari hadn't dropped the ball.

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