{"id":58,"date":"2011-02-04T18:22:36","date_gmt":"2011-02-04T18:22:36","guid":{"rendered":"http:\/\/www.binarydevotion.com\/?p=58"},"modified":"2011-02-09T11:50:14","modified_gmt":"2011-02-09T11:50:14","slug":"scsi-on-the-amiga-cu-amiga-january-1995","status":"publish","type":"post","link":"http:\/\/www.binarydevotion.com\/?p=58","title":{"rendered":"SCSI on the Amiga (CU Amiga Feb 1995)"},"content":{"rendered":"

\"\"<\/a>(Editor note: this was published in January 1995 CU Amiga…\u00c2\u00a0 It might be a bit out of date!)<\/p>\n

SCSI – Standard Computer Systems Interface. Pronounced SKUZZY. It’s a strange word, but it has been, is and still will be one of the best expansion routes available on any computer.<\/p>\n

Put simply, it’s a standard by which peripherals can talk to your computer. The majority of use that SCSI sees is as a way of adding hard drives to a machine, but it can be so much more.<\/p>\n

Currently on the market there are two major interface specifications, these being SCSI and IDE (intelligent drive electronics). Both have vastly simplified the once horrific task of setting up hard drives on a computer by removing the need to type in reams of parameters about the drive before it will work, but SCSI is vastly superior to IDE.<\/p>\n

In theory, both architectures should allow the connection of more than one drive. With IDE you can have two and with SCSI up to seven per interface card. However, IDE drives are quirky – they will sometimes refuse to allow connection of a second disk drive of a differing make from the first. If you’ve got a Connor drive, you’ll want another Connor drive even if there’s a Quantum available at half the price.<\/p>\n

SCSI has no such problems. Plug in – play. I have never found any incompatibilities between drives, providing the controller likes the drives!<\/p>\n

SCSI also scores points from IDE in being incredibly flexible. With it, you are not just stranded with hard disks but you can also connect any SCSI device you can find an Amiga driver for.<\/p>\n

<\/p>\n

“But what’s a driver”, comes the cry from the back of the class.<\/p>\n

A driver is a computer program that literally drives the extra hardware by telling it what do do.<\/p>\n

Since the days of Kickstart 1.3, Amigas have been able to boot from hard disks by allowing drivers to be loaded from expansion cards which can take control of the boot sequence. Unfortunately, this is not the case for other devices – but more about that later.<\/p>\n

SCSI has the advantage that, as its name suggests, it is standard. It has been the standard MAC expansion for some time and cards are also available for the PC to drive SCSI stuff. Unix workstations normally rely on SCSI, too. This has the upshot that there’s a lot of market for them, not just from the Amiga side: it pays to shop around.<\/p>\n

From the back, the same voice as earlier suddenly pipes up with “And where do I start?”…<\/p>\n

First of all, you’ll need a controller to let you connect SCSI things onto your machine. Commodore, in their infinite wisdom, only put SCSI as standard on two machines : the A3000 and the near mythical 4000T.<\/p>\n

Big box amiga owners have it easy. Choose a card, take the case off your machine and plug the thing in – the GVP card still does the job nicely even though it is long in the tooth. 500 owners have a choice again but the most common is the GVP HD8, allowing connection of both one hard disk interally and external devices. 1200 users can look at the GVP RAM\/SCSI expansion card or the recently released Power SCSI-2 add on for their Viper accelerator boards.<\/p>\n

Once you have the board and the drive of your choice, the next part is making them talk to each other. As mentioned previously, SCSI can support up to 7 devices on one controller. Things are connected together in a daisy chain, each device having its own unique address number – this is just so that the interface knows which peripheral to talk to. At the end of the chain, a terminator needs to be used to ‘stop’ signals and complete the SCSI circuit. Consequently, if you are fitting only one device, all you need to do is choose a SCSI address number and check that the termination pack is enabled (check the drive manual for this).<\/p>\n

After physically connecting the drive to the interface, it’s time to let the Amiga know something about the drive. Here, Commodore gain brownie points for an excellent idea : the RDB system. RDB (short for Rigid Disk Block) means that you can, in theory, take a hard disk from a GVP controller, plug it into a Commodore controller and still be able to read and write to the disk. In my experirences, this works well.<\/p>\n

<\/p>\n

\"\"<\/a>

HDtoolbox-boring screengrab, useful tool.<\/p><\/div>\n

The process of setting up your RDB is known as prepping, as you are preparing the drive to have data put onto it. All you need is something that will let you play with RDBs and you’re away. All interfaces I have seen come with software to do this of varying quality. If you don’t like your interface’s software, you’re not stuck with it. Commodore’s HDToolBox works with any device (providing you tell it what the device name is) but as it is not given away with all machines – for no reason – RDPrep from Microbotics sees sterling service as it is both good and PD.<\/p>\n

The RDB of a disk contains (amongst other information) the device names of your partitions, their sizes and lots more about them. A quick explanation of what a partition is may be necessary here: despite the fact that you’ve only got one hard disk, you can split this into as many different chunks (or partitions) as you like. This is why lots of people have only one drive but many icons on their workbench with exciting names such as “System”, “Work” and “Play”.<\/p>\n

I normally advocate using two partitions: one for your workbench software, libraries, fonts and nothing else and another for everything else. You can of course put as many on as you want and this does in some circumstances speed up access to data, but bear in mind that each partition takes memory and that it is incredibly annoying when you run out of space on your “Knitting and rafiawork” partition and so have to start storing unrelated data on your “Zen and the art of Home Brewing” partition. One for all your gubbins, subdivided into drawers, is what I say.<\/p>\n

<\/p>\n

Once your partitions have been set up (maybe 8ish MB for Workbench and the rest for your other stuff), you need to format these disks as at the moment they’re like unused floppies. The FORMAT command on the workbench disk will do this job, but make sure you use the FFS and QUICK flags. FFS stands for Fast File System and basically speeds up disk access. QUICK tells the formatter not to format each individual track (a tedious task) but to just write the information that is necessary to get the disk up and running.<\/p>\n

Now, installing Workbench is necessary. For versions 2.0 or previous, this is simply a case of copying the Extras, WorkBench and Fonts disk to the drive. The CLI command ‘copy’ will do this for you. Boot from your Workbench disk, run a shell and type ‘copy df0: to dh0: all’. Repeat with the Extras disk and Fonts disk.<\/p>\n

Workbench 2.1, 3.0 and 3.1 are slightly more complex: if you want all features to work, you’re best off leaving the task to a program that knows what it’s doing. Most interfaces will come with software to do this, but if it doesn’t First Computer Centre (0113 231 9444) can supply HD-prepping, formatting and installation software at a reasonable cost.<\/p>\n

“Et Voila”, you’re there! You’re in the world of cheap, mass-storage devices. With the going rate of around \u00c2\u00a3600 for a gigabyte of storage, you’ve got it made.<\/p>\n

A word of warning about SCSI drives, though. Flicking through adverts will show pretty vast differences in price between makes and models, even if they’re the same size. Data transfer rates can and do vary wildly, the current zenith being a sustained 5MB\/second from the Seagate Barracuda range (contact White Knight technologies 01920 822321). For this sort of speed, you need a serious interface like a Zorro III Fastlane card which in turn requires an A4000 or 3000.<\/p>\n

There’s also two standards of SCSI interface: SCSI and SCSI-2. SCSI-2 basically allows faster transfer rates from hard drives due to a wider data bus, but SCSI-2 drives can still be used successfully on SCSI interfaces.<\/p>\n

<\/p>\n

Of course, SCSI is not just hard drives. The world of CD-ROM, tape streamers and all is opened up to you. On the CD-ROM side of things, there is a superb PD driver available called AmiCDROM which will allow you to read the majority of CD-ROMs available, be they for Amiga, PC or MAC.<\/p>\n

However, being able to read data from a disc and actually running programs are two entirely different things. You can rush out and buy a collection of PC gifs on CD-ROM, but any viewers on the disk are very likely to be for the PC only, so you will need something like ViewTek or FastGif to view the pictures. There are some excellent viewers in PD, like the ones mentioned.<\/p>\n

Getting down to the actual nitty-gritty, for test purposes an NEC 3xe triple speed external CD-ROM was connected to an A3000 after being graciously supplied by First Computer Centre (0113 231 9444). Again, just plug the drive in after choosing a different SCSI address to existing SCSI devices in the system and set the termination. Here, different interface cards terminate differently when using a combination of internal and external devices. Luckily the 3000 (as with most others) is pretty sensible and allows the last drive internally and the last drive externally to have termination so the drive was connected without any internal fiddling.<\/p>\n

Next, AmiCDROM was obtained from AmiNET (the internet collective of Amiga-carrying FTP sites). Installation was a case of copying the device handler into the L directory of the system disk, copying the file CD0 into the devs\/dosdrivers drawer of the system disk and editing the CD0 file to make sure that the correct device name and unit address were being fed into the handler. For the 3000, the device is scsi.device. GVP controllers need the device gvpscsi.device.<\/p>\n

A quick reboot later sees the disk up and running. SysInfo reported the drive as having a data read rate of 448,232 bytes\/second which shows that the triple speed really does make a difference: this drive is fast!<\/p>\n

<\/p>\n

\"\"<\/a>

CD Player software - free, too!<\/p><\/div>\n

CD-ROMS also allow audio CDs to be played. Jukebox is an excellent shareware program allowing you to do this and is incredibly easy to set up. Again, you just feed in your device name (scsi.device) and the CD-ROM’s SCSI unit number and you have full control of any audio CD you choose to insert into your CD-ROM drive.<\/p>\n

Blittersoft (01908 220196) have recently announced a new piece of driver software for use with AGA amigas. This little beauty will do the previously thought impossible and allow you to play CD\u00e2\u2030\u00a5\u00e2\u2030\u00a4 games on your 1200 or 4000 with a SCSI interface. Priced at \u00c2\u00a339.99 for everything you need, we’ll be reviewing it shortly.<\/p>\n

Tape streamers are invaluable if you have data that you just could not afford to lose on your system. Dumping the whole lot to tape and storing this tape in a different place to your computer protects you against most conceivable disasters happening. BTNtape, again PD, is a handler for tape drives which allows dumping of files to tape. In the commercial world, AmiBack and Quarterback both allow writing to SCSI tape drives when making the backup. An interesting product for tape drive users is a package called TapeWorm FS allowing random access to data on a tape as if it were a hard disk. This is no mean feat: by nature, with a tape you have to advance through data until you find the bits you want. This software attempts to fix this and does so pretty successfully.<\/p>\n

All in all, a SCSI interface will open up another cheap expansion route to your Amiga allowing you to branch out and be more adventurous with your buying. Of course, if you don’t buy from an Amiga dealer, don’t expect support when it doesn’t work with your machine, though…<\/p>\n","protected":false},"excerpt":{"rendered":"

A SCSI-howto article from 1995 for CU Amiga… Now a little outdated!<\/p>\n","protected":false},"author":1,"featured_media":66,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,11],"tags":[],"class_list":["post-58","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-amiga","category-howtos"],"_links":{"self":[{"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=\/wp\/v2\/posts\/58","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=58"}],"version-history":[{"count":0,"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=\/wp\/v2\/posts\/58\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=\/wp\/v2\/media\/66"}],"wp:attachment":[{"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=58"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=58"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.binarydevotion.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=58"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}