SCSI, usb of the 80s

if you've read the title to the video or you looked at the thumbnail you know we're going to talk about scuzzy and if you're under the age of 25 you're probably thinking hey what the heck is scuzzy and B how is that word pronounced scuzzy but before we get into all of that we're gonna have a quick word from our sponsors PCB way a manufacturer wait for it pcbs yes stance a printed circuit board design your circuit board submit it to their website Let It Go for the design rule checks to make sure they can actually make it and you'll get some pcbs back in the post who would have thought they also do injection molding and CNC Machining and you know 3D printing as well anyway we best get back to scuzzy or this won't have been a brief word from our sponsors to look at how scuzzy came to be we're gonna have to cast our minds back to the 1970s a time when in the UK we are not part of the European economic area our economy was basically dying and more or less everyone was on strike a Time completely different to ours it was a time of a lot of change for the computer industry many computers dominated the business space our microcomputers were just becoming a thing and it was during this period a new company was created shugart Associates and the name sugar might be familiar to you particularly if you're familiar with floppy disks as Alan shugart is frequently credited as the man who invented the floppy disk although not quite he's the man who managed the team that invented the floppy disk the people who actually invented the floppy disk were Ralph Flores and Herbert Thompson however shugart and Associates did become essentially the leading manufacturer of floppy discharge during the 70s now one of the problems they encountered during this period of the huge growth in the mini and micro computer Market as to every single one of these machines had their own boss so if you wanted to design something like a floppy disk controller where you'd have to design it for every single machine and each one would be different yes you could reuse bits of the basic design for each one but because each one had to interface with each machine's unique bus a lot of the card was basically unique and if you're a manufacturer of small peripherals to collect into say micros and mini computers this is a pain you spend as much time designing your interface cards to plug into each different machines boss as you do design the actual peripheral you're trying to sell in the first place so this is where shugart and Associates came up with a really nice idea and this idea initially was known as sassy short for shugart associates system interface the core concept behind sassy is it would be a generic bus that could be installed on lots of different manufacturers of computers and peripherals could sit on that so say hard drives Etc the only part that would have to be unique for each machine is The Sassy controller or initiator as it was known that sits in the machine's bus and is essentially the controller of The Sassy boss so if for example you wanted to manufacture a hard drive you could just manufacture a hard drive that speaks The Sassy standard you don't need to make a hard drive controller card that you know fits inside the pdp-11 or a BBC micro or an Altair or whatever it was you had to stick the hard drive onto the controller card could effectively be someone else's problem now this all sounds pretty good but if you want to attract third-party manufacturers to your boss well it's gonna have to become an open standard and this is why shugart and Associates took their bus to ANSI to come up with a standardized version of it and the antsy it became known as standard x3131-1986 a real catchy title it's all right even the American national standards Institute realized that things need a slightly better name than the standards number so sassy became scuzzy small computer system interface the reason they couldn't stick with sassies that contained the company name and and she don't let that be in standard names over how to pronounce it there was actually a little bit of debate um butcher intended for it to be pronounced sexy thought down pronounced it scuzzy and that's the one that stuck the first version of scuzzy is more or less completely compatible with sassy so if you had a sassy hard drive for example it would work on a scuzzy controller and vice versa or at least with the first version of scussy now every time I've talked about scuzzy so far I've mentioned hard drives and scuzzy isn't all just about hard drives although admittedly if you have some passing familiarity viscosity you may have thought of it as just that weird hard drive connector that's not the same as IDE but because he could handle a great variety of devices this is essentially a general small peripherals expansion boss so he can handle a ton of different small peripherals types let's have a quick whiz through some of the things that were commonly used I mean we'll start with hard drives because yeah that that was the big one for scuzzy but that wasn't even just the only kind of disc it could control for example you have these removable hard drives the sysquest cartridges works like a hard drive but removable also it kind of went a little bit crazy with Optical media gonna use a LaserDisc yeah scuzzy bus CD drives when they first came out all because he CD writers again all scuzzy then we get into things like tape drives and oh my goodness there were a lot of those we're gonna cycle back to tapes later on but also it's the most common interface for using any form of large flatbed scanner there are also some pretty expensive printers made use of scuzzy as their interface just because you need to get data in and out of the thing much faster than you would do over a parallel port and strangers to form the one you probably do you didn't expect ethernet cards yes they're ethernet cards that you can connect up to a scuzzy boss and drive them that way in fact a few other different networking types also were available as interfaces for scuzzy there are some pretty weird and wonderful things you could attach to a scuzzy boss in fact if you fall to scuzzy as like a 1980s USB you really wouldn't be very far from the mark particularly if the way you thought about it before was slightly partial version of IDE I think it's probably time we gotta look at the scuzzy boss itself it had two types of connector the internal series that used the flat ribbon and the external type that use this kind of connector and a rounded multi-core cable now on the inside of your computer this flat ribbon type as you can see it's got a number of connectors on it so we can connect many scuzzy devices for external devices you would daisy chain them together but the original scuzzy one standards you could connect eight devices each having an ID from zero to seven and by the time viscosity 2 you get 16 devices numbered 0 to 15. unfortunately with each of these devices you'd have to number them all by hand so either using a little set of jumpers a set of dip switches or in the case of some of the external devices these nice little click up click down type things set in the ID even the controller card in your machine would have an ID also refer to insquez as the initiator normally that I'd have id7 although that was not compulsory is just commonly what people did because it used to be the last ID in the sequence for the original discussing even when we jumped to 1690s people would still leave their controller as id7 the final detail about the physical side of the bus is your bush would need a Terminator yes now I'm not big shootie robot from the films but someone is just there to stop the signals reflecting off the end of the cable and back again now sometimes this would be a big passive brick that kind of went on the end of your external devices or you might have a resistor pack you plugged into the final device on the end of your chain and some devices were even smart enough that they could self-terminate the bus if they were the last thing on it now as you can see the wiring and cabling is very different to the world of USB firstly we have a standard for inside the machine where with USB we don't have a separate inside the machine standard then we have the external standard which is a little bit more USB like in terms of you can plug devices in and out of a port of a machine but we do have some daisy chain together with their own IDs and the connectors do look very very different now the reason for the many many pins compared to USB is this is a parallel standard in the older bits for one byte to transmitter that once or at least in the original standard when it went to the wide version of scuzzy that became 16 bits at once eventually it would become a serial approach we went to the finals because he standard SAS which is serial attached discussing despite the difference in the electrical and cabling standards the next bit is going to seem very familiar to USB users and that's the idea of the generic scussy device a lot of the devices in discussing are your hard drive CD-ROM driver tape drive Etc they can be identified on the scuzzy bus and the operating system doesn't need a special driver for each one it can treat most hard drives the same as long as it reads a little bit of metadata back from the disk telling it how many blocks it's got same with tape drives you can treat them all more or less the same or you could just read back a little bit of information that told it how many tapes it might hold Etc now this is very similar to the idea of USB of the generic device say like the USB mass storage or USB serial ports Etc as these devices behave in a common way with a tiny little bit of variance around their size usually you can just have one from Euros for all of them which saves each hard drive manufacturer having to write a driver or each CD or home drive manufacturer sell on and so forth so again this saves a lot of effort on behalf of the people who are manufacturing the device because they don't have to write special drivers now let's start having a look at some of the computers that adopted it's because he is their standard way to attach stuff so let's start with high-end Unix workstations like from the likes of some SGI Etc even HP now now the reason they use scuzzy disks by default in these machines was for performance reasons they certainly weren't cheaper now at this point in time you'd often be told that scuzzy discs are faster than IDE discs which are the main competition for hard drives now the actual disks themselves didn't go any faster they essentially used the same technology spinning glass platters and heads there isn't really a way to make that go faster for one standard versus the other but the reason people could say that scuzzy was faster is all to do with how the controller worked scuzzy didn't bother the CPU in the same way that IDE did you could also send the command out to one disk why another disc is busy doing something else IDE couldn't do that unless it had multiple controllers one per disk but let's have a look at this claimer that it didn't bother the CPU as much in the world of scuzzy when you want to make a disc do something you get your host controller to send it to command the command goes over the scuzzy busk the disc does its thing and then it replies back to the controller back to the ID that the command came from the controller sat in the machine then you see something called dma with dma the card's allowed to directly transfer the data it's got into memory it then raises and interrupts with the CPU so the CPU know that the card's got something that it needs to have a look at in Ram the situation with the original idea is very different it uses what's known as the i o port on the processor the i o Port is a separate address range instead of pins that are not related to the normal memory bus it's a much smaller address space and when the CPU is using it it has to sit and wait for whatever the response is so say for example it needs to read some data from an IDE disk it would use that I O but send the instructions out to the IDE device and would sit and wait until the idevice comes back and why it's sitting and waiting the CPU isn't doing anything else but the problem is worse than just the sitting and waiting because the CPU needs to read each byte individually back from the IDE device which ties up yet more CPU cycles and this was the problem with IDE it was very CPU intensive the CPU spent time idling Waiting For Stuff the CPU spent time reading and writing every single byte that went in and out of the hard drive and if you're a high-end Unix workstation you really don't want to be blowing all that CPU time on disk access this is why a number of the other 16-bit platforms but non-unix ones standardized around Sky Z2 like the Atari St and the Amiga both of those platforms do not have CPU Cycles to burn on things like disk access the same was true with the 68k max even some of the older 8-bit machines like the BBC micro for example when it got a hard drive controller that was scuzzy based as was its interface for the Doomsday LaserDisc player again let's go see based the only major platform that really did go through IDE was the IBM PC which of course meant that eventually that standard would take over just due to the economies of scale but not before it went through some pretty major changes IDE eventually became a lot more like scuzzy in that two pretty big things happen first of all it stopped using the i o port on the CPU and started having controllers that could you know do dma next it changed how it talks to the hard drive IDE had originally used an addressing scheme of cylinder head sector so your IDE controller had to select which track on the disk it was using which had to select which platter and then which sector on that track where Scotty discs use something called logical block addressing or LBA for short and this is essentially where every block on the disk has a unique number starting at zero and working up and this because the controller just said right to block and gave the number ID eventually swapped over to using LBA as their dressing system too because cylinder sectors heads had a limit of about 500 odd Meg of address space which was fine when a 20 meg hard drive seemed like the biggest hard drive in the world but you know that didn't last very long so Eid introduced the use of LBA moving the standard to Eide meant the IDE hard drives were a lot more competitive with scuzzy ones now into times the performance based around how it loaded the CPU and operating system this is also where you'll see the likes of the Amiga swapping over to using Eid with the Amiga 1200 and the Amiga 4000 at this point it's still true to say that because he still had some performance advantages disk wise over Eide as it could still issue commands to many devices at once and receive responses back from different disks at different times also the command sets a bit neater although you will see that ID swaps over to using the scussy disk command set when it goes to ATA even with IDE starting to take over workstations because he still has a nice niche in the hard disk world and that Niche is basically around servers being able to drive different discs independently is pretty important also not burdening the CPU again pretty important but security at this point also dominates the world of raid controllers and RAID controller Stripes data across multiple physical disks and creates one virtual disk back the operating system the big advantage of a raid system is that if one disk fails well you can take that disc out put in a new disk and rebuild that disk all without losing data there are also some read performance improvements there in that when the computer requests a particular block from the RAID controller the ray controler can fulfill that request from the disc that's not busy rather than having to queue it up for the disk that's already doing something in the red array we would eventually see IDE based Ray controllers but not for quite a long time and even then not at the top high end of the server performance market for quite a while because he also still at the high-end workstation Market kept its space there as well for example for a long time Microsoft recommended that you use scuzzy disks with Windows and team Sun for example ship squishy controls with all their workstations right up until the Ultra 5 and even them on their server models they stuck exclusively viscousy the next major use case for scuzzy particularly in the 90s and well into the 2000s was that of the tape streamer now these devices are not the same as the home data recorder you might have used with your 1980s 8-bit micro there's no analog audio involved in these things oh no there are in fact a huge variety of types of tape available seemed every company in this dog came up with a different one however by the early 90s a number of Standards came to dominate particularly that of dat tape the main use case for tape streamers was that of backup fairly common scenario the early 90s for example was that you'd have a server that contained one or more tape drives and number of shoes that will be backed up remotely to that tape drive there'll be plenty of you in the audience who experience the pain of arcsa for example you would also get personal workstations occasionally with tape streamers in as well particularly you'd see this in the Unix world where our workstation might be used more commonly for scientific and Engineering work so an individual user might generate a number of very large data sets that didn't fit on the workstation's hard drive so you would archive them off to tape in fact the Unix tape archiving system tar still in pretty common use today only these days it's more going at files than tapes in the 80s and early 90s Tate would also be a fairly common in store media for Unix workstations as well in fact that continued a little bit after when CD-ROMs have become a lot more common now tape streamers are pretty much exclusively scuzzy devices virtually all the ones you'll find asking it's not but there were zero devices that use something else but they really were very much a minority I mean for example this one connected to a floppy disk controller Port but this is a very limited functionality kind of device there's a number of things you can do with us because you tape drive you can't do with this one I did also once encounter an IDE bass tape drive as well but that was once I saw someone once and also I was removing it to brother scuzzy one in in other areas because he pretty much dominated initially was that of the cd-rum drive initially pretty much all CD Ram drives were scuzzy based now there's a pretty good reason for that here is because it's because he had already been dealing with these sorts of devices for example laserdiscs and initially until Eide came along and the tappy IDE couldn't cope with a CD-ROM drive in fact they couldn't cope with anything that wasn't a hard disk so there was a big chunk of time where CD-ROM drives are becoming a thing and they're starting to get used on PCS Etc and Eide gaining a tapping so if you were someone who's an early adopter of cd-run you are most likely using scussing as virtually all the CB Ram drives at that point in time were scuzzy devices there was the odd manufacturer of cd-rum drives you had their own audible controller and their drive would work with their CD-ROM controller and nothing else however it is fair to say around when CD drive started to become popular was when a Tapia appeared as this helped reduce the cost of the CD-ROM drive as its Electronics could be a little bit less complicated this oddly didn't mean that for PCs you started seeing IDE controllers with a tappy support getting built onto sound cards because most to the onboard IDE controllers didn't support the CD-ROM drive or the atapi standard we also got to see scuzzy dominate again when CD burners first came onto the market what would them being expensive devices people wanted to use a better controller with them as cozy controllers didn't tend to lead to things like buffer under runs and stuff like that because the operating system was still not quite so busy trying to run a scuzzy device versus an idea of course it's the market for CD burners started to widen and cost started to come down IDE versions would start to appear because cost was the major driving Factor now there were a number of Oddball devices that would appear on scuzzy as well such as removable hard drives like these sysquest cartridges or various other worm formats where you could write it once and read it back many times used for archiving purposes and of course let's not forget about all the flatbed scanners slightly weird printers and for some reason ethernet interfaces but there's one thing that scuzzy can do that none of the other buses I've mentioned so far can do so far I've talked about there being One controller on the bus or initiator if you want to talk about it that way but there's no particular reason in scuzzy there has to be only one there can be more in fact there can be more than one in different machines now some of you at home might be sat thinking why the fudge would I want to do that well I'm gonna tell you fudging why now surprisingly little to do with fudge it does have a lot to do with clustered filing systems however a clustered filing system allows many servers operating in a cluster to all read and write the same file system now admittedly there needs to be some work around locking so two nodes don't try and write to the same bit of the filing system at once or OneNote doesn't try and read a bit of fire system that's currently being modified an example of one of these kinds of filing system is GFS shot for the global filing system here you can have multiple servers connected to the same collection of scuzzy discs usually using raid with GFS sat on top now all the machines using GFR can all send commands directly to the scuzzy disks and get their replies that way you get a fairly high speed filing system shared between all the nodes that are on that scuzzy bus that common scenario for this might be so you have a number of web servers they all want to surf the same content when one gets updated they all want to be updated thus you can use GFS to store your web content and your various servers can then serve that content out to a number of clients assuming each server in the cluster has a decent amount of memory so it can do some caching the discs don't tend to get battered by all the servers connected to them and this technique could be used from the very first version of scuzzy if you wanted all the way up to the very latest now we would see an evolution of this technology in the forms of sans storage area networks allow multiple machines to connect up to lots of different storage arrays and one of the standards you'll notice in this sand space is that of iSCSI which is scuzzy over an IP connection this stops companies having to use specialist fabric like fiber channel I could just swap over to using this stuff over ethernet we should probably have a look at all the different iterations of the scuzzy standard because there hasn't just been one it didn't just get standardized in 1986 and yep that's it we were done so first off we start with Z1 which is essentially sassy more or less that could run a whole five megabytes a second by heck I was eight bits wide we then get fast because of yours because he too was his Otherwise Known and that's very similar to The Originals because he only have cranked up the clock rate so now you can do 10 megabytes a second feel the speed from that our next standard up is known as wide scuzzy which is the same as scuzzy 2 only now it's 16 bits wide and that gives us a whole 20 megabytes a second to play with and also a few more ideas as well we then get Ultra scuzzy which we didn't think that wide fast because he was fast enough now this again is a crank of the clock speed which drags us up to 20 megabytes a second which you might have said wait a minute fast wide because he did 20 megabytes a second and it did and we've gone back to eight bits whiteness but of course there was a wide version of ultra scuzzy I might get this up to 40 home megabytes a second and from Ultra ski we move on to ultra too scuzzy which again comes in the not white and white format which gives us 40 megabytes second and 80 megabytes a second respectively from here we move on to ultra free this time it's not available in the normal and wide format it's just wide now it's always 16 bits from here on in and this gets us up to a whopping 160 megabytes a second that's more Megabytes a second than my first guzzy hard drive had in total so my originals because the hard drive would take less than a second to move with this protocol now you might be expecting Ultra Force because you're at this point but here's where you have a bit of a change in the naming convention now it starts getting named after the number of megabytes a second so it becomes Ultra 320 which does 320 megabytes a second followed by Ultra 640 which wait for it to 640 megabytes a second there are some other terms you'll hear kicking around with these scuzzy standards as well like hvd and lvd shop for high voltage differential and low voltage differential now to start with everything was high voltage differential until we get to ultra too scuzzy at which point things are available in high voltage or low voltage differential so for example hot swappable drives in a lot of servers at that time use low voltage differential as we get discuss the ultra free though everything moves to being low voltage differential one of the incredible things about all these different scuzzy standards is that it's all backwards compatible I could take a scuzzy one disc from the original standard and with the right cables and adapters I can plug it into the latest of the parallel scuzzy standards the high voltage low voltage differential thing did and a little bit more complexity to that but again you can just get little adapter boards that would swap that stuff around for you it's also worth noting that the reverses are so true or at least it is with quite a lot of devices so I can take a scuzzy Ultra 2 low voltage differential disc put the right adapter on it and plug it into original scuzzy one card in fact I have done that yeah in this SJ research mdfs box that only worked with the original scarcity standard yeah I've got a Built for Two disc in there a low voltage differential one to be precise and just a little adapter board and there it is using it because he wanted to face and happily talking to that disc backwards compatibility has actually been a major part in the success factor of scuzzy without each generation supported the devices that came before it people wouldn't have been happy to still keep investing their money in new scuzzy devices now so far we've just talked about the bus and the sort of things that you can plug into it let's briefly have a quick look at the controllers themselves in the PC worlds because the controls were created for every single bus type the PC has ever had starting with your 8-bit Isa all the way through to the latest generation of pcie even our weird side jaunts into the world of eicer and MCA they all had scuzzy adapters too although 16-bit platforms we all used as well that didn't quite survive past the PC period like your Amigas and your Ataris they all had them too in fact here's a nice gvp scuzzy disc that we may have mentioned in another video even some of the home 8-bit micros had scussy cards like for example this massive disc that you could attach to a BBC micro that Drive Unit actually has this because the controller in it and connects up to the BBC's one megahertz bus now a lot of these controllers you've seen they all use a chip from a company called adaptic adaptic was a company founded by two of the people who helped Define The Sassy standard and the whole company's raison Detra was essentially to make because you control the chips and in fact they still do to this day although it did effectively sell off most of its scussy product range which is these days all owned by micro Sammy a bit of adapt that survived that renamed itself to adpt which then that changed its name once again to Steel Excel which is now just an investment firm now that's because you control our ICS were pretty popular and we used a number of cards also adaptic made a whole range of cards of their own too adaptive weren't the only providers because he controllers though again a lot existed and consumed adaptive chips but quite a few did do their own IC design work like bus Logic for example a lot of the high-end security Ray controller providers did a lot of their own work around this like HP and compact for example with their smart array so you might find yourself wondering what the heck has happened to scuzzy it is still alive but we're going to get into that in a in a moment or two we're gonna have a look at at what pushed because the out of its traditional Market position and as I alluded to in the title of the video USB is a big part of it one escuzzy's big Market position was these external devices that you could connect up to your machine CD-ROM drives tape drives you know that sort of thing it's exactly the sort of device we connect up with USB today the problem for scuzzy was USB had a lot of advantages over discussing it was cheaper hot plugging devices in and out was a lot more convenient and supported by the operating system and you get a much greater variety of devices on it too the USB boss was also physically a lot easier to plug and unplug as a scuzzy connectors are fairly unwieldy things and also USB provides power however this displacement is because he didn't happen straight away initially USB was quite a bit slower than scuzzy so in the high end for external discs and CD writers because he very much hung around doing the thing it had always done but by the time we get to USB 2 and then USB 3 the speed problem had been solved and cheaper and convenient was just gonna win but USB owes a lot to scuzzy particularly when it comes to mass storage devices as the USB mass storage device type implements the scuzzy disk command set if you're a Linux user you may have noticed this if you stick a USB storage device in g-computer it shows up as Dev slash SD whatever with the SD standing for scuzzy disk the next treats these things ask a z discs because it uses the same command set so Linux can reuse its scuzzy disc control routines for USB mass storage devices so while USB owes conceptually quite a lot discussing it also has borrowed some actual scuzzy Technologies now the next major area West because he is retreated from is that of the internal hard disk inside your computer scuzzy was the primary disk interface for machines like the Amiga and the Atari and also pretty much all Unix workstations and any high-end PC or server But as time went on IDE seemed to display scuzzy and there's a reason for that IDE became a lot more like scuzzy it started with Eide where Eerie introduced dma so it stopped using the i o boss of the processor it also adopted Scotty's way of doing disk addressing LBA the other major change was IDE disks also adopted the scuzzy command set just like the mass storage device in USB and again Linux uses will have noticed at some point ID devices start from being Dev HD ABC Etc and change to Dev SD ABC again reflecting the fact that they were a lot more like a scuzzy discs you could use discussy disk command routines to drive them West because he still remained relevant in the server market in terms of internal disks is that of the raid array controller high-end servers still use Essentia version of scuzzy known as SAS serial attached scuzzy this is the last evolution of the copper connect standard used by scuzzing and instead of the data Lanes being parallel like they were with the earliest Gazette they've moved to being serial much like when IDE moved from using a parallel boss to SATA which they use now the serial interface they both took this route for the same reason because it's really hard to synchronize bits across multiple data channels at once and as the data rate sped up and the clocking went up keeping all the parallel bits in sync became very very difficult so instead they switched to sending the bits in the serial away I just clocked it up even further now this is the one area West because he is still alive and well and doing its thing it's not the IDE raid controllers don't exist it's just at the high end SAS still dominates although I should mention a dirty little secret as SATA discs use the scuzzy disk command set pretty much every single SAS Ray controller can actually use SATA disks so people do put them in these high-end boxes and have a mixture of SAS discs and SATA disks and if you're wondering why it's because the SATA ones are cheaper although mvme starting to make all of this a little less relevant these days speaking of Technologies they're a little less relevant these days a lot of you will have been screaming but what about fiber channel why hasn't he talked about fiber channel fiber challenge got a lot to do with scussy and and it has the reason I've not really mentioned fiber channel yet is it's one of those technologies that the vast majority of you out there will never ever have used and the reason for this is one of the technologies that underpins a concept called sand the storage area network which is a concept I did briefly mentioned earlier now this is pretty much intended as a data Center Technology and what it allows you to do is keep the world of your storage and your compute separate effectively when you're using a sand the discs don't live inside your computer they live on the separate storage area network and you have Giant Raid boxes full of disks usually a series of fiber channels which isn't some form of controller element as well and when your computer talks to the storage area network it's typically using scuzio for fiber channel now fiber channel is also a technology that's very much on its way out or as pretty much almost gone from everywhere where it's used and that's because it's been superseded by much faster Ethernet from 10 gig on to the 100 plus we now have these days although scuzzy has again kept its hand in there with the isci standard which is scuzzy over IP most hypervisor platforms support isci so if you have a lot of Nas boxes on your network network adapter storage that also support the iscursi standard and most of them do it's a very easy way to glue virtual disks for your VMS to actual physical storage marriage although it should be noted Technologies like cfobs f you want to call it that I really started to eat into this space and they have their own protocol that they use although Seth for example does have an iskuzzy Gateway so things that turquoise because he can still use cephalty for storage and these Technologies use local hard disks inside machines again it's just sometimes you have some nodes that are specialized to be storage nodes although some go for the hyper-converged concept where the hypervisor and the storage is all in a series of identical nodes that play all of the roles if you've got to this point I'd like to say thank you very much for watching I hope you've enjoyed our stroll through the history of skazy and where it's sort of up to today and if you did really like it why not use that thumb shape button below that indicates that fact to YouTube as we are constantly told that that in some way has some positive impact on whether YouTube 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Channel: RetroBytes

Views: 197,694

Keywords: scsi controller, scsi, sasi, adaptec, hard drive, tape drive, sysquest

Id: DB1ve6uicjs

Length: 34min 6sec (2046 seconds)

Published: Sat Feb 18 2023