[cctalk] Re: Gb Ethernet and 10Mb links
Best thing to do is keep an old 10mbit switch or hub around with 100mbit or gigabit uplink. Second best thing is to have a router that will talk 10mbit half duplex. I've also found some poorly behaved stuff that won't autonegotiate duplex even with older switches, like my 3Com SuperStack II. Asante SCSI Ethernet adapters come to mind. Had to set the duplex manually on the switch. Along those lines, 10gig copper interfaces often don't want to talk to 100mbit ports! Found that out when we had a switch fail and stuck an older 10/100 switch in just to get back up and running. Thanks, Jonathan --- Original Message --- On Sunday, May 28th, 2023 at 13:46, Craig Ruff via cctalk wrote: > > > FYI: The Ethernet standards dropped support for half duplex connections a few > years back, so that if you have something that depends on half duplex links a > recent Ethernet switch might not support it.
[cctalk] Re: Getting floppy images to/from real floppy disks.
On Sun, May 28, 2023 at 7:18 AM Tony Duell via cctalk wrote: > > > > Tony, I don't recall what became of the AT with 486 replacement > > processor that used to be your main home machine. ISTR it had loads of > > different floppy drives hung off it. Is it still functional / > repairable? > > Still works, or at least it did when I last powered it up. But no easy > way to read USB sticks or SD cards on it. > > -tony > That sounds too useful to give up on. What about using a gotek drive or similar to put a USB stick on the floppy bus, and/or one of the dos-based 3rd party IP stacks for ftp access ?
[cctalk] Re: Gb Ethernet and 10Mb links
> On May 28, 2023, at 14:18, Paul Koning wrote: > > Dropped support for it on 10 Mb links? That seems like a crazy change to > make. I know it was defined but basically unused at higher speeds. No just the half duplex part of the standard. The 10 Mb/s full duplex links are still supported.
[cctalk] Re: Gb Ethernet and 10Mb links
> On May 28, 2023, at 1:46 PM, Craig Ruff via cctalk > wrote: > > FYI: The Ethernet standards dropped support for half duplex connections a few > years back, so that if you have something that depends on half duplex links a > recent Ethernet switch might not support it. Dropped support for it on 10 Mb links? That seems like a crazy change to make. I know it was defined but basically unused at higher speeds. paul
[cctalk] Re: Gb Ethernet and 10Mb links
I found that out the hard way recently when I acquired my AS/400 and the 10Mb/s card for it. It did not like talking to my 10/100/1000 switch at all. And of course I had recently gotten rid of my old 10Mb/s hub I had been saving for a couple of decades... Had to resort to eBay for an ancient hub. On Sun, May 28, 2023 at 2:09 PM Craig Ruff via cctalk wrote: > FYI: The Ethernet standards dropped support for half duplex connections a > few years back, so that if you have something that depends on half duplex > links a recent Ethernet switch might not support it.
[cctalk] Gb Ethernet and 10Mb links
FYI: The Ethernet standards dropped support for half duplex connections a few years back, so that if you have something that depends on half duplex links a recent Ethernet switch might not support it.
[cctalk] Re: Getting floppy images to/from real floppy disks.
On 5/28/23 09:17, Tony Duell wrote: > I've come across the former and have the datasheets. From what I > recall it was common to use it a control store sequencer and have > microcode ROMs wider than the 8X300 needed, the extra bits were used > to directly control hardware. Power hog (well, it was bipolar) with a 3-bit opcode and a somewhat strange programming model. You could usually spot one by the 50 pin cerDIP and the external pass transistor. I think I still have a loose one in my hellbox--and at least two in old systems. --Chuck
[cctalk] Re: Getting floppy images to/from real floppy disks.
On Sun, May 28, 2023 at 4:36 PM Chuck Guzis via cctalk wrote: > All of these flux-transition gizmos, whether or not they're the > Applesauce, Greaseweazle, Catweasel, Fluxengine, Deviceside work > exactly the same way. A counter free-runs, and every time there's > change in direction of magnetization on a disk, the value of the counter > is sampled. The samples can be stored in memory, or send down a wire to > a host computer. The index pulse is usually included in the sample. Sure, I understand that. But as I have no experience with such microcontrollers I am happy to let somebody else write the code. As for 'all working the same way, that does not mean I don't need documentation. The commands to the controlling software could be just about anything. > Microcontrollers are the natural choice for this, but you could > implement the same in SSI TTL if push came to shove, provided that your > design had the high-frequency headroom. It's not actually all that fast, at least not compared to some things I've worked with. Pulse rates around 1MHz or so. Yes you need to sample faster than that, but it's not a ridiculous rate. I guess that's why a simple microcontroller can do it in software. > > Writing the data back is essentially an exercise in PWM. Again, a good > fit for most microcontrollers. > > All the rest, as they say, is software. > > This is not the way a conventional floppy controller operates, since > they hail from the bad old days of slower-speed logic. Much of the way > they operate is encoded as a state machine in the form of specialized > microcode. In my much younger days I disassembled and commented the microcode in the RX02. And later the microcode in the HP11305 hard disk controller (which is similar in concept). They are elegantly written bits of tight code (as they have to be) but not that hard to understand (a lot harder to write!) -tony
[cctalk] Re: Getting floppy images to/from real floppy disks.
On 5/28/23 07:54, Tony Duell via cctalk wrote: >> I'm suprised to hear you're familliar with the GreaseWeasel but have > Most of my computers [1] use normal FM or MFM disks and I would hope > the Greaseweazle software could handle that.If I can convert to/from a > disk image file I can probably carry on on my own. > > One problem with the Greaseweazle is that there is no documentation. I > would at least have expected the equivalent of a man page. Knowing > what the options are, what it claims to be able to do, etc would be a > good start! > > [1] I do have machines using GCR recording (Apple ][. Sirius (Victor > 9000), etc). And M2FM (DEC RX02). And that odd double-density system > used by Intel in the MDS800. But I can manage without being able to > transfer to/from those, at least at the start. All of these flux-transition gizmos, whether or not they're the Applesauce, Greaseweazle, Catweasel, Fluxengine, Deviceside work exactly the same way. A counter free-runs, and every time there's change in direction of magnetization on a disk, the value of the counter is sampled. The samples can be stored in memory, or send down a wire to a host computer. The index pulse is usually included in the sample. Microcontrollers are the natural choice for this, but you could implement the same in SSI TTL if push came to shove, provided that your design had the high-frequency headroom. Writing the data back is essentially an exercise in PWM. Again, a good fit for most microcontrollers. All the rest, as they say, is software. This is not the way a conventional floppy controller operates, since they hail from the bad old days of slower-speed logic. Much of the way they operate is encoded as a state machine in the form of specialized microcode. There is a fellow from Germany who managed program a PIC MCU (IIRC) to act as a floppy controller (read/write) for (at least) PC MFM floppies. I'll try to find the link in what I laughingly call my bookmarks, if anyone's interested. My feeling is that it was a "proof of concept" sort of thing and relied on some very tight loop code. --Chuck
[cctalk] Re: Getting floppy images to/from real floppy disks.
On Sun, May 28, 2023 at 2:32 PM Adrian Godwin via cctalk wrote: > > Tony, > > An instrument slightly more to your taste than a PC might a 16500b logic > analyser. Perhaps you've already got one. I believe these can work with > both LIF and MSDOS floppies and uses an IDE HDD (which can painlessly be > replaced with CF card) in DOS format internally. I don't know if it will > handle other than 3.5" formats but it's quite possible that the support for > those formats is generic and it might work, given an appropriately mangled > hardware interface. Well, the hardware might be capable of doing other formats but it might not. Most if not all of the HP HPIB disk units are hardwired to be double density only, as is the HP4951C protocol analyser's internal disk controller and I could well believe a logic analyser would be the same. Standard PC floppy disks and all 3.5" LIF floppy disks are double density after all. In any case to handle other formats you'd have to do battle with the 16500's firmware whch I doubt is documented at that level. And I don't think schematics of the instrument exist anywhere, I believe the HP1630 was the last HP logic analyser to have schematics in the service manual (I do have one of those). If I want to do that much work I might as well make my own system from scratch. One problem with that (and a major plus-point of things like the Greaseweazle) is that traditional floppy disk controller ICs are either discontinued or at best EOL'ed. I don't like designing round parts that might not be available. -tony
[cctalk] Re: Getting floppy images to/from real floppy disks.
> I'm suprised to hear you're familliar with the GreaseWeasel but have > never heard of BlueSCSI. ( https://scsi.blue/ ). Though SASI > compatability seems "possible but not guaranteed", being an open source > project, you can probably wangle the existing PCB's/software to be SASI > compliant. More research, that i can leave you to perform, will probably > help with that endeavor. The only reason I've heard of the Greaseweazle is that it was recommended to me. I did ask at the start of this thread about other similar flux-transition interfaces but got no real information. On the grounds I could get a Greaseweazle easily, it was fairly inexpensive and it's open-source I've decided to give it a go. Still not managed to get the software working, which is probably down to the Windows installation on this machine. But I am going to take the adviceof some more knowledgeable friends before I change anything. I suspect that making a SASI-SD interface is something I could attempt myself. > Anyway, you seem to truly have your heart set on the Greaseweasel. As > long as you can write, or find, software that can turn the Weasels > output into something useful, i'm sure it will suit your purposes fine. > Of course, if you're archiving software froma truly unknown format, it > will almost definitely be the best solutions. Getting useful data into > and out of it is where the trouble will be. Most of my computers [1] use normal FM or MFM disks and I would hope the Greaseweazle software could handle that.If I can convert to/from a disk image file I can probably carry on on my own. One problem with the Greaseweazle is that there is no documentation. I would at least have expected the equivalent of a man page. Knowing what the options are, what it claims to be able to do, etc would be a good start! [1] I do have machines using GCR recording (Apple ][. Sirius (Victor 9000), etc). And M2FM (DEC RX02). And that odd double-density system used by Intel in the MDS800. But I can manage without being able to transfer to/from those, at least at the start. -tony > > Good luck! > > > Josh
[cctalk] Re: Getting floppy images to/from real floppy disks.
-- Original Message -- From: "Tony Duell via cctalk" To: "General Discussion: On-Topic and Off-Topic Posts" Cc: phi...@axeside.co.uk; "Tony Duell" Sent: Sunday, 28 May, 2023 At 07:17 Subject: [cctalk] Re: Getting floppy images to/from real floppy disks. I suspect USB-SCSI interfaces exist but I've not looked into one. Since SCSI is a 'formatted' interface it shouldn't be too hard to make pseudo disk drive using flash memory. I must look into that to make a SASI drive for my P2000C. I'm suprised to hear you're familliar with the GreaseWeasel but have never heard of BlueSCSI. ( https://scsi.blue/ ). Though SASI compatability seems "possible but not guaranteed", being an open source project, you can probably wangle the existing PCB's/software to be SASI compliant. More research, that i can leave you to perform, will probably help with that endeavor. As for a means to interface SCSI to USB, they do exist, but are often expensive and of debatable compatibility. You will almost always have a much better experience with a SCSI PCI card in an (and i don't mean to push the subject) older PC. Still works, or at least it did when I last powered it up. But no easy way to read USB sticks or SD cards on it. -tony The XT-IDE ISA card is probably what you'll want. Though it doesn't "natively" support SD cards, there are IDE/CF adaptors to SD cards that can provide a means and ways of interfacing an older PC with modern media. ( https://users.glitchwrks.com/~glitch/xt-ide.html ) Anyway, you seem to truly have your heart set on the Greaseweasel. As long as you can write, or find, software that can turn the Weasels output into something useful, i'm sure it will suit your purposes fine. Of course, if you're archiving software froma truly unknown format, it will almost definitely be the best solutions. Getting useful data into and out of it is where the trouble will be. Good luck! Josh
[cctalk] Re: Getting floppy images to/from real floppy disks.
Tony, An instrument slightly more to your taste than a PC might a 16500b logic analyser. Perhaps you've already got one. I believe these can work with both LIF and MSDOS floppies and uses an IDE HDD (which can painlessly be replaced with CF card) in DOS format internally. I don't know if it will handle other than 3.5" formats but it's quite possible that the support for those formats is generic and it might work, given an appropriately mangled hardware interface. -adrian
[cctalk] Re: Getting floppy images to/from real floppy disks.
On Sun, May 28, 2023 at 07:17:54AM +0100, Tony Duell via cctalk wrote: > On Sat, May 27, 2023 at 8:47 PM philip--- via cctalk > wrote: > > > > > > > USB interfacing is hard, but SD cards are a lot simpler. So use a card > > > reader thing to transfer the files to an SD card and design an > > > interface for that to ISA bus. > > > > Thinking of that, I had actually wondered whether one could transfer the > > appropriate image files from a modern PC (internet access) to a classic > > PC (disk drives) using a SCSI hard drive. Not if the modern PC is a > > laptop, I suppose. > > I suspect USB-SCSI interfaces exist but I've not looked into one. Adaptec USB2Xchange is one that kept popping up when I looked for just such a thing years ago. Acquired one some time ago (from EBay, because of course the product has been EoL for years). Haven't used it yet, but it presumably works reasonably well. > Since SCSI is a 'formatted' interface it shouldn't be too hard to make > pseudo disk drive using flash memory. I must look into that to make a > SASI drive for my P2000C. There is a whole collection of SCSI device emulators out there and they usually tend to use SD or CF cards for actual storage. > I suspect it's easier to use CF cards. At least some USB card readers > can handle those. And the interface is essentially the same as the IDE > hard disk It helps that a lot of the pro DSLR cameras used CF as storage for quite some time, so card readers for CF should be easy to find. Kind regards, Alex. -- "Opportunity is missed by most people because it is dressed in overalls and looks like work." -- Thomas A. Edison
[cctalk] Re: MCAS (was: Re: Getting floppy images to/from real floppy disks.)
On Sat, May 27, 2023 at 10:00 PM Alexander Schreiber via cctalk wrote: > Which is why among the more cynic^Wexperienced SREs (my line of work) > we sometimes use the term "Working As Implemented" when the code behaves > exactly as written (and ofteni as specified), but still does the wrong > thing because it (usually) was written with wrong assumptions. I generally say 'Broken as designed' meaning it does what the design says it should, but what the design specifies is stupid. I often say that about bits of the ISA bus and things designed for it, for example. -tony
[cctalk] Re: Getting floppy images to/from real floppy disks.
On Sat, May 27, 2023 at 8:47 PM philip--- via cctalk wrote: > > > > USB interfacing is hard, but SD cards are a lot simpler. So use a card > > reader thing to transfer the files to an SD card and design an > > interface for that to ISA bus. > > Thinking of that, I had actually wondered whether one could transfer the > appropriate image files from a modern PC (internet access) to a classic > PC (disk drives) using a SCSI hard drive. Not if the modern PC is a > laptop, I suppose. I suspect USB-SCSI interfaces exist but I've not looked into one. Since SCSI is a 'formatted' interface it shouldn't be too hard to make pseudo disk drive using flash memory. I must look into that to make a SASI drive for my P2000C. I suspect it's easier to use CF cards. At least some USB card readers can handle those. And the interface is essentially the same as the IDE hard disk > > Tony, I don't recall what became of the AT with 486 replacement > processor that used to be your main home machine. ISTR it had loads of > different floppy drives hung off it. Is it still functional / repairable? Still works, or at least it did when I last powered it up. But no easy way to read USB sticks or SD cards on it. -tony
