On the first day they were available (August 12,1981, IIRC), my employer bought two 5150s. One had 16K and MDA. The other had 64K, a 64K expansion card, a serial card, and CGA. The first thing we did was add 48K of RAM to the 16K unit. Then we designed and sold our own 256K RAM cards and floppy controller cards.

On 31 July 2013 17:18, <schoedel at kw.igs.net> wrote: OK. Perhaps I should clarify: I was not doubting you or questioning your machines, merely expressing my own first thought. I guess it would be possible to have some kind of terminal emulator for the PC in 16K, one which talked directly to the NIC, but if so, how would they have loaded it? From cassette? That seems implausible to me but then I was not using PC tech in 1981. I was 13 and saving up for my Sinclair Spectrum 48K. :?) -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884

Il giorno mer, 31/07/2013 alle 10.43 -0700, Chuck Guzis ha scritto: Well, what tape reader was 5150 compatible? -- Retromuseum: http://www.supervinx.com/Retrocomputer You can reach me at: http://www.youtube.com/supervinx http://www.myspace.com/supervinx http://www.facebook.com/supervinx

Just about any cheap mono audio cassette recorder? The pinout of the IBM cassette socket was (as Fred said) the same as the TRS-80 Model 1 (and Model 3, Model 4, CoCo, M100, M200, etc). You could use the Radio Shack cable which had a 5 pin DIN plug on one end (to fit the computer) and 3 jack plugs (phone plugs to you?) on the other. One for the remote control, one for singnal from the computer to the tape, the last for the signal from the tape to the computer. The output signal level is eelctable by a jumper link on the IBM 5150 system board to eith either 'Microphone' or 'Aux' level. The input signal is about what you'd expect from an earphone output When the IBM PC came out IBN did not sell a tape recorder or cable. I am told you were supposed to go down to the local Radio Shack and buy said items. -tony

They _must_ appear on E-bay from time to time. Incidenatlly, the Dragon 32 is aonterh amchien that uses the same cable. The connectors are certainly still available (well, they were on the rack in the Maplin shop I was in today...). It is just a cable, no electronics inside, so it would not be hard to make one up. I think I would use twin screended cable for the audio signals nad a separate cable for the remote switch just to keep PSU noise out of the audio signals. The pinout of the DIN plug is : 1 : Remote control (Say to sleeve of the 'remote' plug) 4 : Signal to computer (Tip of the 'Ear' plug) 2 : Ground (Sleeves of the 'Aux' and 'Ear' plugs) 5 : Signal from computer (Tip of the 'Aux' plug) 3 : Remote control (Tip of the 'remote' plug) Note that pins 1 and 3 can be swapped round. The DIN plug pins are not numbered in the obvious aorder. They are 2 4 5 1 3 Looking at the face of the socket (wire side of the plug) -tony

On 7/31/2013 12:48 PM, Chuck Guzis wrote: I didn't know that - I have IBM Diagnostics on Cassette tape that came with the machine. I just found it strange that the diagnostics would come on cassette tape but there was never an IBM cassette player. I guess there really was a plan... Rob.

On Wed, Jul 31, 2013 at 2:45 PM, Rob Doyle <radioengr at gmail.com> wrote: And as far as I know, there was no official IBM explanation of where to get a suitable cable. As mentioned earlier in this thread, the salesmen at ComputerLand and such places generally would tell you to go to Radio Shack and buy the TRS-80 cable (p/n 26-1207), but I don't think IBM ever officially suggested such a thing. When my employer purchased on on the first day of availability, we didn't even think to ask. We noticed that the connector was the same as the TRS-80, so we tried a cable we already had, and were pleasantly surprised that it worked. Eric

[IBBM 5150 cassette port] Unfortuantely not everybody bought the TechRef..... The only time I've seen an all-plastic plug on the Radio Shack cable is the one that came with my first (early) Model 1. That DIN plug locked in place, you had to pull abc kthe collar to release it. All later cables (the ones that cabe with later machines, with the EI, with cassette recorders [1]) have ahd conventional metal-shell plugs. AFAIK the DIN socket used on the IBM 5150 is the same part as the one used on a TRS-80 Model 1. Not just a 5 pin type A DIN socket, but the exact asme PCB mounting part. So unless the plug body fould the PC case or something, any cable that fits a TRS80 Model 1 will fit an IBM 5150. [1] At some point Radio Shcak stopped includign the cassette cable with the machine and bundled it with some of their audio cassette recorders instead (the 'CCR' -- Computer Cassette Recorder -- range IIRC). You could still buy the cable separately, but most shops over here didn't keep it in stock, it had to be ordered. It was marketing, pure and simple. If you bought a computer and the cable was included you could buy your cassette recorder anywhere. If you had to order the cable then a lot of people would pay the extra to get the recorder+cable there and then.... -tony

On Thu, 1 Aug 2013, Tony Duell wrote: They used two identical connectors for vastly different purposes, because Radio Shack had done the same with THREE connectors. That let them show the world that they were so big that they had no intention of learning from somebody else's mistakes. But, in this case, it worked! Whew! And thus is born "Industry standard cassette cable"

Il giorno mer, 31/07/2013 alle 13.45 -0700, Rob Doyle ha scritto: Well, did you save the cassette content into an audio file? I'd like to have a copy, if possible... -- Retromuseum: http://www.supervinx.com/Retrocomputer You can reach me at: http://www.youtube.com/supervinx http://www.myspace.com/supervinx http://www.facebook.com/supervinx

Might be a good moment to remind people that AEK uploaded a set of IBM's internal PC newsletters here: http://bitsavers.trailing-edge.com/pdf/ibm/pc/pc/personal_computer_newslett… Has anyone done any digging in these documents about this early PC model referenced in this thread? I found a few interesting tidbits about IBM Displaywriter in these newsletters that was not otherwise known (to me).

On 7/31/2013 5:13 PM, Fred Cisin wrote: The Diagnostics came with the base diagnostics to test the system. Each subsystem you bought had a diagnostic disk with it which could be punched and used as a blank disk for all the use it did. I think the Advanced diagnostics came with a separate package, and was not unavailable, just had to know the right order number. It was probably held back by resellers, but I never had a problem going to IBM here and getting a copy of the thing. Resellers could charge you to install your disk and set the system up if they held that back. Jim

On Wed, 31 Jul 2013, Alexandre Souza wrote: Then, therefore, this extraordinarily rare item must be worth enormous amounts of money?

Easy to find in Brazil, even the special models made specifically for a said computer (like DR1000 from CCE, or the special datacorder from Gradiente and sharp for the MSX computer, etc). A very common k7 recorder used in Brazil was the RQ-2222 (and somewhat the RQ2211) from national/matsushita/panasonic

On 8/2/13 9:13 AM, Peter Corlett wrote: The one reason is to use the full track width instead of two stereo tracks. I had some strange effects when dubing some old interviews from cassette with a stereo deck that went away when I found a NOS Panasonic. Those things were made for a VERY long time. Of course, the plastic transport and belts are crap.. I still have to experiment using it to recover a box of VERY old Sphere casettes.

On 8/3/13 5:00 AM, Peter Corlett wrote: You REALLY need to deal with the DC300's and DAT tapes because the rubber in the drives WILL fail if it hasn't already. DAT and 8mm was never very reliable to begin with. The tension belts in the DC300s have most likely lost tension as well. Floppies aren't as big a deal. If they are in a format that a PC floppy controller can deal with you probably have at least 10 years to image them. The only thing that should fail in that time span will be the drive belts on 8" drives that have them. I expect that if you squirrel away enough 3" or 5" drives with direct drive that the media you could read today will still be readable then if stored in a cool low humidity environment. I've read several thousand disks from Don Maslin's collection this year and had very high recovery success even though they had been stored in a hot humid storage locker for the past five years. It was of value to learn that the Shugart double-sided drive seems to be significantly less prone to carving concentric grooves in the media than Qume full-height or half- height drives. The heads are also much easier to get at to clean. I've also been reading a very large collection of MS-DOS era 5" disks that were stored in a hot but dry environment (Stockton) and haven't had too much trouble. The exception are Brown Disks and Memorex, but that is a known problem. I would suggest, though, that you think about prioritizing what you have saved. It isn't difficult to dig around the web to see what has already been read. Unfortunately, people have been doing a pretty sloppy job of keeping track of things like if it was read from original media, if a game, if its' cracked, etc. We just received a donation of several hundred original Apple II game disks, for example, and I have not been able to find anything to tell me the provenance of the images that are already out there. I'm not very excited about going through them, since I know that almost all of them will be copy protected. Something else I wonder about is why Deluxe Option boards still sell for so much money with the better alternatives that are out there now. Are there disk image files floating around in the underground that only work with hacked software for that board? You couldn't save images to disk with the software that shipped with the board for obvious reasons.

On 08/02/2013 09:13 AM, Peter Corlett wrote: You'd be surprised. Cassettes are still being produced, and, at least according to some in the industry are more popular than ever. See, for example: http://nationalaudiocompany.com/ and the squib in the August 12, 2013 issue of Time magazine, on page 56 notes that the still-popular media format is now 50 years old--like TTL ICs. The interesting thing is that I've picked up Nakamichi cassette decks (definitely not cheap) for nothing via the loca Freecycle. --Chuck

On Sat, Aug 3, 2013 at 4:08 PM, Chuck Guzis <cclist at sydex.com> wrote: Though as far as I can tell, chrome and metal tape are no longer made. I never used metal tape back in the day, but I used a lot of Maxell UD-XLII and UD-XLIIS chrome tapes, and some TDK SA, and new old stock has become very scarce and expensive. A friend just gave me a Nakamichi Dragon, which won't auto-reverse but is otherwise fully functional. I really wanted a Dragon back in the day, but they were way too expensive for me. Eric

At 5:34 ?pm +0100 2013/07/31, Liam Proven <lproven at gmail.com> wrote: Not at all; I didn't think so. As it happens, now that I have had a chance to look at it, the network card in the machine is not one of UW's own, but rather an IBM/Sytek PC LAN interface from 1984. -- Kevin Schoedel <schoedel at kw.igs.net> VA3TCS

On Wed, 31 Jul 2013, Liam Proven wrote: POSSIBLE. Not particularly likely, since floppies were available, and RAM [IFF you did not buy it from IBM] was a TRIVIAL expense to bring it up to 64K. Easier, as ONE vendor did, to sell the 64K for one price, and the version for use in 16K for a bit more money, since the 16K version included 27 chips that you had to plug into open sockets on the motherboard. THAT ploy was handy for dealing with Board Of Education types who sometimes had a software budget, but no hardware budget.

On 07/31/2013 06:28 PM, Liam Proven wrote: I could certainly see stuffing a terminal emulator into the 8KB of a 64Kbit PROM (24-pin 8KB Moto EPROMs (e.g. 68765/66) work just fine) shoved into the extra (unpopulated) ROM socket of a 5150 (U28). 8KB of ROM would certainly be useful for many terminal protocols. I don't know if it was ever down, however. --Chuck

Just looks like Brazil! :oD And I don't have a Bell & Howell (or something like that, I just don't remember) black apple :(

On Wed, Jul 31, 2013 at 12:41 PM, Fred Cisin <cisin at xenosoft.com> wrote: And 12.5% more cost. When the PC market moved to SIMM memory (predecessor of DIMM), that led to companies selling fake parity SIMMs, by putting a parity generator chip on the SIMM instead of the RAM chip for the parity bit. Eventually PCs stopped having parity at all. Mainstream x86 processors support ECC, which is much better than parity. DIMM modules are either 64-bit (no ECC) or 72-bit (with ECC), so the overhead is the same as for parity, but ECC corrects the errors instead of locking up the machine. However, most people are still unwilling to pay extra for ECC. Intel disables the parity circuitry on most of their x86 processors other than their server (Xeon) processors, to use it for product differentiation, thus raising the cost of ECC far above just the cost of the RAM. AMD x86 processors all have ECC enabled. That's one reason I prefer AMD in systems I purchase. Unfortunately ECC is generally not available in laptops. Eric

Alas TRS-80 RAM 'kits' cotnained 8 chips... Of coruse if you dealt with a suppleir who sodle the loose chips you could buy the required 9 of them. Some years later over here wer had the Amstrad PCW machines. Some of those came with 256K RA Mas standard (no partiy, just 8 41256-like ICs) and could be upgraded to 512K by plugging in another 8 similar ICs. Some suppliers sold RAM upgrad kits for said machines which included an extra chip to practice putting into the socket. Needless to say these kits were just re-labeleld sets of 9 DRAMs for PC upgrades with a sheet of instructions). There was even the right connector on the SGA board for said modulator, complete with power connections. -tony

On Wed, 31 Jul 2013, Chuck Guzis wrote: no worse than TRS80, other than trying to get 80 column (PC also supported 40 column) Certainly! ALWAYS use a B&W monitor (monochromatic RS170 compatible, disunirregardless of phosphor color) That gives usable text (for some levels of use), whereas most color composite monitors had too coarse a pitch. I didn't have the skill to modify a monitor, nor the funds to buy a good one, so all of my early machines were B&W composite monitors, such as CCTV. -- Grumpy Ol' Fred cisin at xenosoft.com

On 07/31/2013 11:41 AM, Fred Cisin wrote: This was also the time of the US "Let's shoot ourselves in the foot" anti-dumping trade sanctions against Japanese semiconductor makers. So any DRAM was in short supply and expensive. For my 5150, I used some Intel 2109s that happened to pass diagnostics on the PC for 16Kb. ...and parity does not cause a machine to "lock up". What it does do is trigger a non-maskable interrupt. The default action for that vector on the 5150 is to display a message and halt--but that does not preclude the user from supplying his own handler that returns control to the interrupted code. I'd rather know about a memory error than discover that my program was producing garbage. Seymour Cray is often credited with saying "Parity is for farmers" when the 6000-series machines lacked parity checking on memory. It's also worth noting that his later machines not only had parity but also SECDED. --Chuck

On Thu, 1 Aug 2013, Christian Corti wrote: Yes. and 5 slots, with wider mounting plates than XT cards, and a 63-65W power supply Some of the early ones had additional blocked off holes in the back panel Some had a screw coming up from below mounting the floppy. Some had a black power supply. Some had a white narrow power switch.

On Thu, 1 Aug 2013, geneb wrote: There was once an external drive that ran a power connection through that hole. But then they started putting power supplies in all the external drives. (bad idea to try to power too much external stuff off of 63W)

On Wed, 31 Jul 2013, Michael Holley wrote: BEFORE the XT 5160 came out, the PC was updated to a 64K/256K motherboard. Unlike the XT, WHICH CAME SLIGHTLY LATER, the PC had 5 expansion slots, and a cassette port. Some "journalists" called the 64K/256K PC a "PC2", but IBM never used THAT terminology. Considering the shortage of slots on the Apple2, what does the design with 5 slots tell you about IBM's ability to learn from OTHER people's mistakes? The 64K/256K could be upgraded with trivial ease to 640K, by replacing two rows of 64K chips with 256K chips, and adding one additional chip (don't remember what that add-on chip was. XT eliminated the cassette port, and incresed from 5 to 8 slots, although ONE slot (closest to the power supply) skipped one buffer and was incompatible with some cards. IBM solved THAT by plugging the hole with a "FREE!!!" serial/20mA card (which they had excess inventory of, and couldn't sell well because EVERY multi-funcion card had serial. Q: You and every other multi-function card vendor have clock, RAM, serial, and parallel. That's 4 functions. How do you compete with EVERY OTHER 4 function card? A: You call your card "SIX function". You do THAT by adding a RAM-DISK program (similar to the PC-DOS VDISK), and a PRINT-SPOOLER. NOTE: The AST and Quadram FPUIB docs have been claimed. My employer (college administrators, may they rot in pieces) offered "HALF PRICE!", but the deal was NOT half price of your choice of parts; it was "half price" at ~$2300 for a system bundled with every piece of crap that wasn't moving, such as Easy Writer. The multi-function cards started coming out in 1982. WELL BEFORE THE XT 5160. With 5 expansion slots, a complete system needed mult-function. But, the first after-market board that I bought for mine was the Boulder Creek Systems? RAM card - 192K with ECC! -- Grumpy Ol' Fred cisin at xenosoft.com