Posts Tagged ‘Hardware

14
Dec
17

SS20 Desktop: Kernel Issues

Over the past few weeks I’ve been continuing my work trying to get the latest NetBSD working on my Sparcstation 20. The system has been hanging and I’d had trouble working out why, so I turned to reading as much as I could to see if I could find any clues. I found in the mailing list someone suggesting that not all SCSI drives are co-operative with the on board controller when running a MP (multi-processor) kernel on later versions, so I looked through my collection of SCA drives to see if I had a different model I could try. I found I had an IBM Ultrastar disk that is around 18G in size, so I swapped the Fujitsu drive (model MAJ3182MC) out for it. Surprisingly this made my system behave much better, it would install, and run on the uni-processor kernel with no issues at all where the fujitsu drives seemed to cause the system to hang frequently under disk access.

However booting with a MP kernel still would hang within about 20 minutes or during disk access, so it was at this point I joined the mailing list to ask others what I could do to resolve the issue. The people on the list are quite friendly and have been very helpful in trouble shooting. It seems that there are some kernel bugs related to MP that are present in 7.1 that are at least partially resolved in more recent versions of the kernel. Like most open source OS’s the current stable release is behind by a version or two from where the developers are currently working. It seems that there is some possibility of the fix being back-ported to 7.1, I tested out a patched MP kernel that was greatly improved in this respect. It still hung, but after a much longer period of time, and only when provoked by a specific program. Feedback from the mailing list also seems to indicate that choosing not to use the on board SCSI is another way that I could work around the problem.

So I now have multiple options for running my system. I could switch to using a single processor, I’d have the option of either a 60Mhz SuperSparc (currently installed with a dual 50Mhz module) or 75Mhz Ross HyperSparc, and everything should work well. Alternatively I could acquire an SBus SCSI card to connect my hard drives, or forgo a local disk entirely by using networking booting and a NFS share, both avoiding having to use the on board SCSI. Finally I could use the system as it is now with the patched 7.1 kernel, it worked well enough that this is quite feasible. I’m leaning towards booting the machine over the network at the moment.

In the short term with Christmas approaching, I’ll be putting the project aside until I have more time in the new year.

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16
Nov
17

SS20 Desktop: Some minor progress

Whilst it has been some time since the original post, I have been a busy beaver trying to get the old Sparcstation 20 running. I’ve been making an effort to get the hardware working with some mixed success, and have made much better progress with the software.

The hardware is of course the much more pressing matter for obvious reasons. I had a recurrence of the problem I had with stack under run errors and just general problems booting in general. Of course this lead me to suspect the hardware, so this week I went about trying to work out what exactly was causing the issue. One way to help determine which part is at fault is by stripping the system back to the minimal and gradually add components while testing the system in between. Having removed most components the stack under run symptom didn’t disappear, trying each memory stick individually didn’t improve things, so I began to fear the worst as surely not all the RAM I have is faulty. It was at this point I decided to run the set-defaults command to reset the computers configuration despite not seeing anything there that should cause any issues, this funnily enough seemed to do the trick, as far as getting the machine to the open boot prompt without any errors and passing all the diagnostic tests with everything installed. I had to scale back to a 17G fujitsu HDD as the larger one didn’t cooperate with the system.

At this point I breathed a big sigh of relief as my hardware is probably in working condition. It’s booting the OS (NetBSD 7.1) and seems to run fine with one problem. Random system hangs. There doesn’t seem to be any pattern such as when the machine is loaded down or network access. I’m guessing that the kernel is having some issue and tries to hand control back to the system ROM, but this some how hangs/fails. I might try running the machine with out the X server in case it is stopping any errors from being displayed. I looked into the kernel messages and noted a few devices that may also be the culprit. The kernel is detecting the on board graphics (comes up as sx0 in the messages) even though I do not have a VSIMM installed, as I’m using a SBUS graphic board instead. The audio chip in my machine is listed as a DBRI, which is known to have issues with the current kernel driver. If you try to play audio in any manner the system hangs, it’s been a bug for a while, it kinda worked under NetBSD 4.0 when I last had that running. With this in mind I’m building my own kernel with the drivers for these two devices and other unnecessary devices removed.

I’ve had much more luck getting software to build in my emulated machine. I’ve got a fairly large collection of software to try out. Although I did have trouble much earlier on when either QEMU or the emulated machine would hang during a build. I can’t be sure if that’s down to the emulation or if it’s a genuine issue with the OS, and a possible cause of my problems on the real machine. Whilst I haven’t really changed anything in the emulation, it hasn’t hung for quite a while, so it’s any bodies guess as to the cause when it did happen.

Progress has been slow, but I’m gradually getting there! I’ve seen some cheap Ross Hypersparc 90Mhz modules that I’m considering buying as an upgrade.

19
Oct
17

Motherboard: EPoX EP-8K3A

Today’s motherboard is a Socket 462 board (also known as Socket A) it is an EPoX EP-8K3A made in early 2002. The CPUs that fit this socket type have an exposed die that makes direct contact with the heat sink, this is generally good for heat dissipation, but makes installing or removing a heat sink a risky business. Here’s a photo of the board.

The board has a VIA KT333 chip-set, which at the time was one of the first to support the then new DDR333 standard. VIA chip-sets were very common at the time, especially where AMD CPUs were installed. An interesting feature was it’s ability to run the memory and FSB clocks asynchronously, although in practise this wasn’t that useful. If the memory was slower it became a bottle neck for the entire system. If it was faster the CPU wouldn’t have been able to make full use of the extra bandwidth, although that bandwidth could be used by other devices such as a graphic or sound card. Also noteworthy is the fact that this is a single memory channel board, later systems made use of the dual channel architecture which had a memory bandwidth advantage.

It has the usual suspects as far as peripherals go. It has a HDD/FDD controller, Serial/parallel ports, two USB ports, AC97 audio and a game port, which would have covered most users needs at the time. It lacks on-board LAN and USB 2.0, which would have been nice to have, but are easily added via the 6 PCI slots. There were two models, one had extra IDE ports connected to a RAID controller along with a diagnostic module that displayed the status on a two digit seven segment display. I have the board without these extra features, which doesn’t worry me as I can add a RAID card if needed.

EPoX was known for making boards for the enthusiast and over-clocker, and this board doesn’t disappoint on that front. You can see the voltage regulation circuitry has more capacitors and chokes than contemporary boards. They called this three-phase, but that’s not really a good description, basically it has three separate voltage regulator circuits just for the CPU core voltage. This results in a power supply with less noise on the line, and with the larger capacitor bank it also handles spikes in workload/power drain better. It probably increased the boards reliability over the long term, even if you didn’t over-clock. I found a review of the board that was written at the time it was released that has more details.

By the time this board was made jumpers were mostly a thing of the past, with everything under software control in the BIOS settings generally. With the front panel connectors clearly marked this board would have been quite easy to install and set up for an end use. This board would have been favoured by technicians partly because of this, but also because it would have almost certainly been more reliable, was fairly cheap, and was even forward compatible with processors and RAM that was yet to be released.

For end users this would have been a great work horse board for anyone, it is cheap, reliable, and has extensive upgrade options. However now as an old board, there are better socket A boards from the era with more features, better compatibility and faster chip-sets more capable of over-clocking. It would still be good in a vintage PC build, but not for a high performance machine of the era.

24
Aug
17

Motherboard: Another unknown Socket 3

Today I’m looking at another 486 socket 3 motherboard that unfortunately I can’t identify. Unlike the last one, this one actually had it’s model number on the silk screen, but the OEM who put it into a machine has covered the silkscreen label with either white paint or white out so that it is unreadable. Obviously this is a massive pain as I have no chance of finding a manual for this board, which is needed because of the large number of jumpers. I suspect they didn’t want end users finding out that it was a low quality board. Here’s a photo.

Again it’s a later 486 board as it has PCI slots rather than VLB slots. Reading the date codes on the chips reveals it was made in mid 1995, around the same time as the other socket 3 I have. The chipset was made by UMC, which I’m unfamiliar with. After having done some forum lurking over at VOGONS and reading some of the Red Hill Guide, it seems that it’s a fairly common chipset found on a variety of boards. I can’t comment on the performance myself, but others have had success getting decent performance out of their chipsets.

There are very few integrated peripherals, it has an old school DIN keyboard connector and two IDE ports, but strangely no floppy disk controller, serial or parallel ports. This ultimately wouldn’t have saved much money for the end user as they’d have to use add in cards to replace the functionality. Weirdly the IDE ports each use different styles of socket, another sign of cheapness.

The cache chips and system ROM are all socketed, which is a good sign that the cache is probably not a fake. The EPROM unfortunately had the sticker missing, exposing the window for the UV erasable chip. I’ve since put my own sticker over the window to protect it.

In an effort to identify it, I decided to pull the ROM chip and read it in my TL866 universal programmer. I was hoping to find a string that had the model name in it directly,but after an extensive search I only found the BIOS version string, “2A4X5B05”, which was enough to identify the manufacturer as Biostar but not the model.

Another unfortunate feature of this board is this real time clock chip with integrated battery. The idea is great in theory, but results in an unusable board when the battery runs flat, which it has.  Some of these RTC chips had the option of an external battery, unfortunately this isn’t one of them, so the only option I have is to either replace the chip (it’s not socketed) or hack it open and attach an external battery. Unfortunately this board doesn’t even remember the settings through a warm reboot, preventing it from actually booting an OS.

Like many 486 boards much of the basic configuration is done with jumpers. This usually means looking them up in the manual, but this board does have the basic settings for voltage, FSB speed and L2 cache size. Still there are obviously many more jumpers that are undocumented on the board, so the manual would be really handy. Luckily the silk screen has enough information you could install a CPU and not make the magic smoke escape.

At the time this board was made it was fairly low end, and windows 95 was just around he corner. It would have probably performed ok with MS-DOS and Windows 3.1, but would have been inadequate for Windows 95 when it came out later the same year. Most 486 machines didn’t really perform well with windows 95 so that’s hardly a surprise. The lack of integrated peripherals is probably the worst point with this particular board, as you’ll need add-on cards even for basics such as a floppy drive and serial port (which you’ll need for a mouse). Otherwise it would have made a serviceable, but not powerful machine.

01
Jun
17

SparcStation Desktop project.

Unfortunately I’ve been neglecting my poor old Sun hardware, mostly because of time and space constraints. I thought I’d try to go some way to correcting this by actually beginning the process of setting up the SparcStation 20 as a vintage desktop work station. I’d been planning on doing this for ages, as long ago as when I built the replacement server machine.

Hardware wise I’ve not acquired anything new, although everything needed a test and some basic cleaning to get it working. I’m still having issues, but I’m unsure if it’s an hardware fault or a problem with the software I’m installing. We’ll get to the software in a moment, first we’ll look at the hardware installed.

At the moment I have 3 CPUs in the machine. They are all V8 Supersparcs with two 50Mhz chips on one module and a 60Mhz one on a module on it’s own. Each module has 1Mb of cache memory which doesn’t sound like much now, but was a large amount when these machines first appeared.

Frame Buffer

Frame Buffer

I’ve currently got about 304Mb of memory installed, I had more but unfortunately one of the sticks that was in it fails to detect anymore. I’d like to have a VSIMM as that would allow me to use the built in cg14 frame buffer (graphics card) which is probably the best performing one available for machines of it’s type. I managed to purchase a 2Mb TGX+ frame buffer and adapter to connect it to a VGA screen, which is doing an odd resolution of 1152×900 at 8 bits per pixel. It’s obviously not the fastest, but it does the job. I’ve selected an 136Gb 10K RPM SCA drive for the hard disk, certainly a bit of overkill, but it would just be sitting on my shelf otherwise.

The initial issue I had was stack under run errors after the boot screen came up and the machine attempted to boot. My first instinct was of course failed memory, which lead me to find the undetected memory module. But no matter which memory I ran I had the same problem. After some poking into the system environment (kinda like the BIOS settings in the PC but without the nice interface.) I found some items that were not at their defaults and changing them back seems to have fixed the stack under run.

Dual CPU MBUS module

Dual CPU MBUS module

Unfortunately that’s not the end of the issues, as after installing and running NetBSD for a while the machine will hang, reset or have a watchdog timer trigger. This certainly could be faulty RAM, but the power supply is also a potential suspect as is the operating system itself. I need to follow this up with some more testing, unfortunately I don’t have a spare PSU to test with.

Software wise I’m much more prepared and have had much more success. I’ve been using Qemu, which does full-system emulation for a number of old and different platforms, including Sparc systems. Qemu has been useful for building packages and the kernel specifically for my machine. Something I had done ages ago when I first intended to do the install.

At the time I built for NetBSD 6.1.4 which is the OS I’ve installed and tried out on the machine. It’s out of date by quite some margin now, so I’ve set up a new virtual machine to start work on getting 7.1 packages and kernel built. It has a bunch of improved hardware support, particularly in the frame buffer acceleration, so I’m keen to see how it goes. I’m still building packages I want for it, but I’m happy with 7.1 under qemu so far. I’m hoping the improved hardware support helps with the hang/watch dog/reset issues.

When it’s all done, I’ll post about what it’s like to use the machine for specific tasks, like say browsing the web and checking email.

05
Apr
17

Motherboard: Aopen AX34-U

I’ve been rather busy of late, and it’s been raining here in buckets, so finding the time for photographing a board has been tricky. In any case I had some time today and have found a socket 370 board made by Aopen.

I wasn’t able to decipher the date of manufacture from any of the date codes on the board, but it’s almost certainly made around the early 2000’s. It supports the Tualatin and Coppermine cores of the Pentiun III and Celeron chips. The Coppermine ones had a reputation of being quite good at over-clocking at the time.

Looking at the board as a whole the layout is pretty standard for the time, although I’m puzzled as to why the AMR slot is right next to the AGP slot. I’ve never seen an AMR card in the wild, probably because they were pretty poor software modems. On this board it occupies what would be a prime spot for a PCI slot, which I’d much rather have.

You’ll also note it still has a legacy ISA slot, something which disappeared from consumer hardware in a few short years around the time this board was made. ISA slots stuck around for a surprisingly long time, partly due to the amount of hardware that was made for it. It was used for many unusual cards some for controlling industrial machines. I have one somewhere that was used as a lighting controller for dance floor lighting in a pub. Machines made for industrial conditions kept the ISA slot for much longer.

Unfortunately this board seems to have suffered leaky caps, a common cause of failure for many electronics. One has coated a surrounding chip with it’s goo. This kind of problem can be repaired, but it isn’t usually done because of the time or cost involved if you pay someone to do it. If you have the time, patience and skill you can clean up the goo and replace the caps, often restoring the device to functionality. I’m not confident I can repair this yet, as my soldering skills are pretty much hobbyist level. It’s easy to damage a board like this as it has very fine traces and small pads designed for machine assembly.

Performance wise this would have been quite a nice piece of kit. It has a VIA Apollo Pro 133T chipset which was a reasonable performer as well as being cheaper than alternatives. It had room for 1.5Gb of RAM providing you used the expensive-at-the-time 512Mb modules. With only 3 SDRAM slots you couldn’t use many of the cheaper sticks to make up the difference, but few people were going for more than 0.5Gb of RAM at the time.

From a technicians point of view it’s fine in terms of specs, but the board silk-screen isn’t as helpful as others when connecting the front panel and setting jumpers. The front panel is marked, but isn’t real easy to read, which can be worse in the tight confines of a case. Luckily there aren’t too many jumpers as software controls much of the settings, most of the jumpers you won’t need to touch with perhaps the exception of the one that sets the FSB speed. The manual is also still available if you need further help.

As an end user this would have been quite a good buy, it has most things you need integrated (except NIC) and has a decent chipset with support for a decent range of configurations. You could build either a cheap and cheerful machine, or something with pretty good performance with a board like this one.

 

02
Nov
16

Campbell Scientific C20 Cassette interface

Today we’ve got something unusual, a RS-232 Cassette interface made by Campbell Scientific. They seem to have always been specialised in making data logger and acquisition system. I can’t be sure, but I think this device was used for storing digital data on audio cassette, a common media of the time. Micro computers of the time did this as well, but usually had this function built in. It’s likely that this would have been used with machines that didn’t have that capability natively, like a PC or perhaps some scientific equipment that can speak RS-232.

It’s built in a very sturdy and quite large metal enclosure. It feels very well made, the few switches on it (including the small DIP switches) feel like quality components that have held up quite well.

The enclosure probably could have been smaller, but here you can see it probably wasn’t specific to this one device. The card cage only houses two cards here, but could have had 5 which would have been enough room for something more complicated.

Here is the processor board, it has a Z80 CPU which would be running at 4Mhz. Around it are mostly simple logic chips in the 74 series, but directly bellow the CPU are two 2k word x 8bit SRAM chips as well as the EPROM. Interestingly the SRAM chips (CDM6116AE3) were used in the memory expansion socket on the MPF-1, I may be able to use one of these to expand my unit. Handily every chip is socketed, so repair (or salvage) is significantly easier. The board appears to have been designed by hand, as you can see many of the traces are quite curvy, it’s clear a great deal of care went into its design.

The front panel board has very similar construction, everything in sockets and hand designed PCB. All the input and output circuitry is on this board and includes a Z80 serial IO chip and two CTC (counter timer circuit) chips. Given that this is a tape interface there is a distinct lack of DAC or ADC chips, most of the smaller chips are 74 series logic, a couple of opamps and serial line drivers and receivers. I suppose other machines (like the ZX spectrum) didn’t have those chips for storing digital information on tape, so they probably use a similar technique. It does make it clear that analogue or audio data is not supported by this device.

I’m a bit conflicted about what I’ll do with this particular device, the collector in me says keep it, but I don’t have a lot of space or use for it. I may end up just keeping the boards for parts, as they are all fairly usable chips with data sheets available.

 




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