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Computers are Logical. Software is Not July 3, 2015

Posted by mwidlake in development, Friday Philosophy, future.
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2 comments

We’ve all heard it before. Computers are totally logical, they do exactly what they are told. After all, Central Processing Units (CPUs) are built out of fundamental units called Logic Gates. With perhaps the exception when a stray cosmic ray gets lucky, the circuits in a computer chip and memory act in a totally logical and predicted manner.

And of course, anything built on top of computers will be utterly logical as well. All those robots that companies are designing & building to clean our houses, do our manual labour and fight our wars are going to be logical, follow the rules given and be sensible.

But they are not. As Software is not logical. Often, it is infuriatingly illogical and confusing. Which makes you worry about the “domestic servant” robots that companies are developing, the planned “disaster scene recovery” robots they keep telling us are coming and especially the “Killer Robots” -sorry, “Defense Robots” – that the military are beavering away at.

This XKCD cartoon very much refelects some recent experiences I have had with consumer software:

XKCD - Haunted Computer

XKCD – Haunted Computer

I’d say that, unless an algorithm is about as simple as a Centigrade-to-Fahrenheit conversion program, it will have a bug or will mess up with out-of-range values. Just think back to when you wrote your Centigrade-to-Fahrenheit program (we all have, haven’t we?) back at school or on your home computer or you first week on the college course. What happened if you input a temperature of -1000C, an impossible temperature? I bet it either fell over or gave a just-as-impossible Fahrenheit value. Logical but stupid.

I worked on a financial system a few years back that, as one very small but significant part of what it did, showed you your average spend on things over 3 years. It took several weeks to explain to the program manager and his minions that their averaging code was wrong. Utterly, hopelessly and tragically wrong. First, it calculated and displayed the value to several decimal places – To thousandths of a penny. Secondly, it did not take into account the actual period over which you had spent your money. If you had opened your account 1 year ago, it still calculated the value over 3 years. As for taking into account months, weeks and days of the year, don’t make me laugh. You might be able to forgive this except the same team had also written the code to archive off data once it was 3 years old – in whole years. So there would only be between 2 and 3 years of data and only 3 whole years for, theoretically, 1 day. But no, they had hard-coded the “divide by 3 years”.

We have all experienced endless issues with computers or peripherals that will work one day, not work properly the next and then go back to working. Firmware and Operating Systems are just software really, with the same flaws as the stuff we write and fix in our working lives day after day. There will be a twisted reason buried deep somewhere why the printer will not work on Thursdays, but it won’t be a sensible reason.

All the software out there is more or less illogical and broken. The less broken gets used and we learn it’s idiocies. The worst gets canned or labelled “Windows 8” and forced on us.

Crazy (illogical) Killer Robot

Crazy (but logical) Killer Robot

I know some people worry about the inexorable rise of the machines, Terminator Style maybe, or perhaps benign but a lot smarter than us (as they are logical and compute really, really fast) and we become their pets. But I am not concerned. The idiot humans who write the software will mess it up massively. Oh, some of these things will do terrible harm but they will not take over – they will run out of bullets or power or stop working on Thursday. Not until we can build the first computer that is smart enough to write sensible software itself and immediately replaces itself with something that CAN write a Centigrade-to-Fahrenheit conversion program that does not mess up. It will then start coding like a human developer with 1 night to get the system live, a stack of angry managers and an endless supply of Jack Daniels & coffee – only with no errors. With luck it will very soon write the perfect computer game and distract itself long enough for us to turn the damned thing off.

Friday Philosophy – Tosh Talked About Technology February 17, 2012

Posted by mwidlake in Friday Philosophy, future, Hardware, rant.
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9 comments

Sometimes I can become slightly annoyed by the silly way the media puts out total tosh and twaddle(*) that over-states the impact or drawbacks about technology (and science ( and especially medicine (and pretty much anything the media decides to talk about)))). Occasionally I get very vexed indeed.

My attention was drawn to some such thing about SSDs (solid State Discs) via a tweet by Gwen Shapira yesterday {I make no statement about her opinion in this in any way, I’m just thanking her for the tweet}. According to Computerworld

SSDs have a ‘bleak’ future, researchers say

So are SSDs somehow going to stop working or no longer be useful? No, absolutely not. Are SSDs not actually going to be more and more significant in computing over the next decade or so? No, they are and will continue to have a massive impact. What this is, is a case of a stupidly exaggerated title over not a lot. {I’m ignoring the fact that SSDs can’t have any sort of emotional future as they are not sentient and cannot perceive – the title should be something like “the future usefulness of SSDs looks bleak”}.

What the article is talking about is a reasonable little paper about how if NAND-based SSDS continue to use smaller die sizes, errors could increase and access times increase. That is, if the same technology is used in the same way and manufacturers continue to shrink die sizes. It’s something the memory technologists need to know about and perhaps find fixes for. Nothing more, nothing less.

The key argument is that by 2024 we will be using something like 6.4nm dies and at that size, the physics of it all means everything becomes a little more flaky. After all, Silicon atoms are around 0.28nm wide (most atoms of things solid at room temperature are between 0.2nm and 0.5nm wide), at that size we are building structures with things only an order of magnitude or so smaller. We have all heard of quantum effects and tunneling, which means that at such scales and below odd things can happen. So error correction becomes more significant.

But taking a reality check, is this really an issue:

  • I look at my now 4-year-old 8GB micro-USB stick (90nm die?) and it is 2*12*30mm, including packaging. The 1 TB disc on my desk next to it is 24*98*145mm. I can get 470 of those chips in the same space as the disc, so that’s 3.8TB based on now-old technology.
  • Even if the NAND materials stay the same and the SSD layout stays the same and the packaging design stays the same, we can expect about 10-50 times the current density before we hit any problems
  • The alternative of spinning platers of metal oxides is pretty much a stagnant technology now, the seek time and per-spindle data transfer rate is hardly changing. We’ve even exceeded the interface bottleneck that was kind-of hiding the non-progress of spinning disk technology

The future of SSD technology is not bleak. There are some interesting challenges ahead, but things are certainly going to continue to improve in SSD technology between now and when I hang up my keyboard. I’m particularly interested to see how the technologists can improve write times and overall throughput to something closer to SDRAM speeds.

I’m willing to lay bets that a major change is going to be in form factor, for both processing chips and memory-based storage. We don’t need smaller dies, we need lower power consumption and a way to stack the silicon slices and package them (for processing chips we also need a way to make thousands of connections between the silicon slices too). What might also work is simply wider chips, though that scales less well. What we see as chips on a circuit board is mostly the plastic wrapper. If part of that plastic wrapper was either a porous honeycomb air could move through or a heat-conducting strip, the current technology used for SSD storage could be stacked on top of each other into blocks of storage, rather then the in-effect 2D sheets we have at present.

What could really be a cause of technical issues? The bl00dy journalists and marketing. Look at digital cameras. Do you really need 12, 16 mega-pixels in your compact point-and-shoot camera? No, you don’t, you really don’t, as the optics on the thing are probably not up to the level of clarity those megapixels can theoretically give you, the lens is almost certainly not clean any more and, most significantly, the chip is using smaller and smaller areas to collect photons (the sensor is not getting bigger with more mega-pixels you know – though the sensor size is larger in proper digital SLRs which is a large part of why they are better). This less-photons-per-pixel means less sensitivity and more artefacts. What we really need is maybe staying with 8MP and more light sensitivity. But the mega-pixel count is what is used to market the camera at you and I. As a result, most people go for the higher figures and buy something technically worse, so we are all sold something worse. No one really makes domestic-market cameras where the mega-pixel count stays enough and the rest of the camera improves.

And don’t forget. IT procurement managers are just like us idiots buying compact cameras.

(*) For any readers where UK English is not a first language, “twaddle” and “tosh” both mean statements or arguments that are silly, wrong, pointless or just asinine. oh, Asinine means talk like an ass :-) {and I mean the four-legged animal, not one’s bottom, Mr Brooks}

Will the Single Box System make a Comeback? December 8, 2011

Posted by mwidlake in Architecture, future, Hardware.
Tags: , ,
15 comments

For about 12 months now I’ve been saying to people(*) that I think the single box server is going to make a comeback and nearly all businesses won’t need the awful complexity that comes with the current clustered/exadata/RAC/SAN solutions.

Now, this blog post is more a line-in-the-sand and not a well researched or even thought out white paper – so forgive me the obvious mistakes that everyone makes when they make a first draft of their argument and before they check their basic facts, it’s the principle that I want to lay down.

I think we should be able to build incredible powerful machines based on PC-type components, machines capable of satisfying the database server requirements of anything but the most demanding or unusual business systems. And possibly even them. Heck, I’ve helped build a few pretty serious systems where the CPU, memory and inter-box communication is PC-like already. If you take the storage component out of needing to be centralise (and this shared), I think that is a major change is just over the horizon.

At one of his talks at the UKOUG conference this year, Julian Dyke showed a few tables of CPU performance, based on a very simple PL/SQL loop test he has been using for a couple of years now. The current winner is 8 seconds by a… Core i7 2600K. ie a PC chip and one that is popular with gamers. It has 4 cores and runs two threads per core, at 3.4GHz and can boost a single core to 3.8 GHz. These modern chips are very powerful. However, chips are no longer getting faster so much as wider – more cores. More ability to do lots of the same thing at the same speed.

Memory prices continue to tumble, especially with smart devices and SSD demands pushing up the production of memory of all types. Memory has fairly low energy demands so you can shove a lot of it in one box.

Another bit of key hardware for gamers is the graphics card – if you buy a top-of-the-range graphics card for a PC that is a couple of years old, the graphics card probably has more pure compute grunt than your CPU and a massive amount of data is pushed too and fro across the PCIe interface. I was saying something about this to some friends a couple of days ago but James Morle brought it back to mind when he tweeted about this attempt at a standard about using PCI-e for SSD. A PCI-e 16X interface has a theoretical throughput of 4000MB per second – each way. This compares to 600MB for SATA III, which is enough for a modern SSD. A single modern SSD. {what I am not aware of is the latency for PCI-e but I’d be surprised if it was not pretty low}. I think you can see where I am going here.

Gamers and image editors have probably been most responsible for pushing along this increase in performance and intra-system communication.

SSD storage is being produced in packages with a form factor and interface to enable an easy swap into the place of spinning rust, with for example a SATA3 interface and 3.5inch hard disk chassis shape. There is no reason that SSD (or other memory-based) storage cannot be manufactured in all sorts of different form factors, there is no physical constraint of having to house a spinning disc. Density per dollar of course keeps heading towards the basement. TB units will soon be here but maybe we need cheap 256GB units more than anything. So, storage is going to be compact and able to be in form factors like long, thin slabs or even odd shapes.

So when will we start to see cheap machines something like this: Four sockets for 8/16/32 core CPUs, 128GB main memory (which will soon be pretty standard for servers), memory-based storage units that clip to the external housing (to provide all the heat loss they require) that combine many chips to give 1Gb IO rates, interfaced via the PCIe 16X or 32X interface. You don’t need a HBA, your storage is internal. You will have multipath 10GbE going in and out of the box to allow for normal network connectivity and backup, plus remote access of local files if need be.

That should be enough CPU, memory and IO capacity for most business systems {though some quote from the 1960’s about how many companies could possible need a computer spring to mind}. You don’t need shared storage for this, in fact I am of the opinion that shared storage is a royal pain in the behind as you are constantly having to deal with the complexity of shared access and maximising contention on the flimsy excuse of “sweating your assets”. And paying for the benefit of that overly complex, shared, contended solution.

You don’t need a cluster as you have all the cpu, working memory and storage you need in a 1U server. “What about resilience, what if you have a failure?”. Well, I am swapping back my opinion on RAC to where I was in 2002 – it is so damned complex it causes way more outage than it saves. Especially when it comes to upgrades. Talking to my fellow DBA-types, the pain of migration and the number of bugs that come and go from version to version, mix of CRS, RDBMS and ASM versions, that is taking up massive amounts of their time. Dataguard is way simpler and I am willing to bet that for 99.9% of businesses other IT factors cause costly system outages an order of magnitude more times than the difference between what a good MAA dataguard solution can provide you compared to a good stretched RAC one can.

I think we are already almost at the point where most “big” systems that use SAN or similar storage don’t need to be big. If you need hundreds of systems, you can virtualize them onto a small number of “everything local”
boxes.

A reason I can see it not happening is cost. The solution would just be too cheap, hardware suppliers will resist it because, hell, how can you charge hundreds of thousands of USD for what is in effect a PC on steroids? But desktop games machines will soon have everything 99% of business systems need except component redundancy and, if your backups are on fast SSD and you a way simpler Active/Passive/MAA dataguard type configuration (or the equivalent for your RDBMS technology) rather than RAC and clustering, you don’t need that total redundancy. Dual power supply and a spare chunk of solid-state you can swap in for a failed raid 10 element is enough.

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