The A590 HARD DISK DRIVE and MEMORY EXPANSION UNIT for the A500 Most of us agree that the Amiga 500 is a great machine. However, almost immediately new owners start to look for extra RAM (Random Access Memory) and a second disk drive. Fortunately the Commodore A501 512 Kbyte RAM expansion module (complete with battery backed up clock) is available at a very reasonable price, and a second disk drive can now also be purchased again at a reasonable price. Even so, as the software base expands to take advantage of the amazing capabilities of the Amiga, this 1Mb, two floppy drive configuration can still be a severe limitation when it comes to running the more serious 'productivity' and graphics software especially when multitasking several applications at once. 'Power' users will next be on the lookout for more RAM and a hard disk drive. Up till now availability of these items has been a rather haphazard affair in Australia. Although it has been possible for some time to buy memory expansion units and hard drives from a limited number of local and imported sources, concerns about supply and the lack of support from local dealers and distributors have meant that many A500 owners are still waiting for something with an established pedigree to appear. This is now about to happen with the forthcoming release of Commodore's own A590 unit. The unit combines a 20 Megabyte hard disk drive unit with an (unpopulated) memory expansion unit, which can be built up to take another 2 Megabyte of RAM. Initial Impressions. The A590 comes in a beige case which matches the appearance and colour of the 500 and looks quite neat when it's attached to the 86-pin systems bus on the left side of the Amiga. This unit comes complete with its own separate power supply which is automatically switched by the A500. If the final manual is anything like the preliminary copy we have seen, the user will be supplied with all the information required in a well designed format. As it arrives in the box, the hard disk is formatted to 20Mb and has the complete 1.3 Workbench is already installed. Unlike with the A2000/2090 systems, you don't have to mess about with foreign things such as 'mountlists' and Prep/Format commands etc., nor do you have to plow through the manual with trepidation on what to do first. At last, all you have to do is plug it in and turn on the A500 and 20 seconds or so later you are greeted with workbench. (NOTE: Only applies for Kickstart version 1.3. Users of version 1.2 must boot from the floppy disk supplied.) Of course, a better idea would be to actually to read the manual first! INSIDE THE A590 Inside, the A590 has an Epson HD755 20Mb hard drive and HMD755 SCSI controller, as well as an XT (ST506) interface. Sockets are provided so that system memory can be expanded in steps of 512 Kbytes, 1 Mbyte or 2 Mbytes. To populate it you need the 256K x 4 DRAM chips with a speed of 120 ns. or faster. At present day prices one should be able to purchase the 2 Megabytes of RAM for approximately $500.00. (July 89, but memory prices seem to be coming down in price?) If you are not technically inclined it pays to have the memory chips installed by a qualified technician as they are very susceptible to static charges (especially in this weather). It is not unknown for people to 'blow' them during installation. However, if you feel competent, the manual has explicit instructions on how to go about the job and which jumpers to set, depending on the amount of memory which you are installing. Another internal jumper will have to be set if you wish to use the alternative standard SCSI interface instead of the XT interface. EXTERNAL On the back of the unit are four dip switches, the power connector, and a standard 50 pin SCSI connector allowing you to add up to seven SCSI devices onto the system. (A SCSI - Small Computer Systems Interface- bus is similar in some respects to the 64/128 serial port, in that each device has its own unique device number allowing easy daisy-chaining of hard drives, printers, scanners, CD-ROM drives etc.) Before you can start using your hard drive certain dip switches have to be set on the back of the unit, depending on your system's configuration. Switch one needs to be set for either Kickstart version 1.2 or 1.3. If you are using Kickstart version 1.3 you can 'auto-boot' with the 590. This means that, when you switch your computer on, the hard drive will automatically boot up without having to insert a Workbench disk in drive DF0. Switch two has to be set if several units use the same physical address space, as the system only expects one 'Logical Unit Number' or one unit at every physical SCSI address. Switch three is only needed for certain expansion hard drives which take more than 30 seconds to come up to speed (e.g. certain Seagate drives); this is the so-called 'Time-out Length' switch. (On the 2000/2090A systems, this function is not available so for auto-booting one must make a careful choice of hard drive unit itself!) Switch four is not currently implemented, it's for future expansion. THE HARD DRIVE. As supplied, the hard drive comes formatted under the FastFileSystem. An internal DMA (Direct Memory Access) chip gives you a theoretical maximum data transfer rate of 2.4 Megabyte per second. Interestingly, this is the first auto-booting controller from Commodore itself which allows booting directly from the FastFileSystem. With the 2000/2090A systems one must have a 'standard file system' partition on the start of the drive to auto-boot from. Commodore are working on a 'hard-card' for the A2000s to be named the A2901(?) and from looking at the driver software with the A590, it would appear that the A2091 may well be based on this A590 interface. Since we have read several adverse comments about the slow data transfer rates of these particular Epson drives, the performance of the interface appears to be quite effective achieving very respectable data transfer speeds. (See below for the actual performance figures.) Unfortunately, because of time constraints we have not yet been able to test out the SCSI interface part of the unit. To most users performance figures really mean very little, so a couple of examples may give you a better idea. The PageStream program comes on two floppies and takes 2 minutes and 30 seconds to boot up. The same program installed on the 590 takes only 26 seconds! That is more than 5 times as fast and is quite impressive. For a second example, Professional Page loads from the A590 in approximately 35 seconds compared with more than 3 minutes from floppy. [Ed: As a comparison, it takes 27 secs on my 40-meg Miniscribe, with a custom controller from Hard Disk Technologies in Adelaide. Hard Disk Software. As we have said the hard disk is supplied formatted and has the complete 1.3 Workbench is already installed. Supplied with the unit is a 3 " 'A590 Setup' disk. This is a bootable WB 1.3 disk containing all that is required for Kickstart 1.2 users to boot the drive plus extra utility software you may require should you ever need to setup, format the drive, or perform other functions such as adding extra drives etc. (NOTE 1.2 Users: You MUST boot from this disk since it contains all the device driver software for the interface and definitions for the hard drive itself.) Programs include Park and HDToolbox and several 'clickable' XICON script files are provided to make life easy. These include FormatHD, PrepHD, InstallHD, InstallStartup, MakeBootDisk. Unfortunately, the A590 interface and driver software does not provide an 'auto-park' option as does the 2000/2090A. The PARK program 'parks' the read/write heads of the hard drive out of the way of the data tracks providing a safe landing zone for the heads when the drive is switched off. This program should always be run before you transport the unit to prevent both damage to the unit, as well as loss of data. The InstallStartup script will copy the 1.3 Startup-sequence on your hard drive. The MakeBootDisk script is used if you are still using Kickstart 1.2. (Probably a good time to install 1.3 Kickstart to make use of the hard drive's auto-boot facility.) If you wish to make changes to the partitioning of the drive or add new drives to the unit (including via the external SCSI connector), the HDToolbox program provides a relatively friendly solution. This program is a dramatic improvement over the A 2000s 2090A where all such changes must be done using a text editor and 'mountlists'. The software also permits validation of the drives and mapping of defective blocks etc. All these programs, as well as an explanation of hard drive terminology, are very well documented in the manual that comes with the unit (Commodore's manuals have definitely improved over the last couple of years). The only omission from the 'Setup Disk' is a hard drive backup program, but fortunately there are quite a few good Public Domain programs available, as well as some excellent commercial ones. Performance Tests. We have experimented with the A590 for some time now under a wide range of conditions. The unit has behaved well on all tests we have thrown at it. The access and load/save times for this unit compare favorably with most other drives and interfaces of a similar type available on the A500 and A2000 systems. If anything the interface appears to perform slightly better than the A2090A auto-boot interface for the A2000 and equally as well as various third party A500 units. Considering that the actual hard drive in the A590 is not the fastest in the world, the overall results are well up to standard. It will be interesting to see how well it performs when connected to one of the better SCSI drives such as the Quantum HQ80s which achieves transfer rates of the order of 650K/sec on the A2090. To show the relative performance of the A590 unit, we used the PD program 'DiskPerf2'. We have been using this program for several months to compare different drives and interfaces available for the Amigas and it gives a fair idea of performance. One severe problem with the A2090 and A2090A interfaces for the A2000 is the unbelievable slowdown when the Amiga is displaying a large 4 bit-plane (16 colour) image. (The 2090A is even worse than the 2090! This appears to be due to the fact that the intermediate drive buffers are allocated by the auto-boot code into 'slow' memory.) This problem is caused by bus contention between the Amiga and the DMA from the drive. It is most evident with SCSI type drives. For example, when displaying large overscan multicolour images for video graphics work, we have measured a speed drop from 450K/sec to LESS THAN 10K/sec, a more than 45 times slow down to less than the speed of a floppy drive! With ST506 type drives (similar to the drive in the A590), the problem is not so evident. (Commodore have not intention of fixing this problem at present, apparently because they are working on the A2091 hard-card!) Tests on the A590 showed only minor slow down (approximately 10%) under these conditions. The following results should be treated like most standard tests, in that they only reflect the results of these specific tests. However, they do give a good indication of the type of performance one can expect from the unit. But, go an see one demonstrated for yourself! We have included diskperf results for a standard floppy drive (running under the 'standard file system') for general interest and by way of camparison, the results for a 2000 with a 2090A interface with a Miniscribe 3650 44Mb hard disk combination. Diskperf Performance Tests on A590. A590 2090A/Miniscribe Create 11 file/sec Scan 95 file/sec C 11 S 94 Delete 19 Seek/Read 56 D 38 S/R 86 A590 Floppy 2090A/Miniscribe Buffer Read Write 512 16,010 15,100 8,260 3,504 47,489 19,661 4K 99,826 74,472 12,192 5,060 100,824 84,399 8K 129,774 91,658 12,358 5,100 122,497 97,814 32K 180,415 105,445 12,315 5,067 154,202 109,867 64K 180,415 126,030 " " 154,202 109,546 256K 189,137 152,409 " " 157,349 115,686 OVERALL COMMENTS One comment that has been made is that "it's only a 20 Meg hard drive", and to some extent this criticism is justified, but let us take a quick look at the facts.... A 20 Megabyte hard drive is equivalent to about 22 3 " disks. If you intend to install a series of application programs on the hard drive, you will find that you can install a lot more than 22 disks on the A590, because you need only one copy of the Amiga operating system on this disk (i.e. one C directory, one DEVS directory, one LIBS directory etc.). In fact, you only install the actual program and its associated files and not the operating system. This can mean a saving of up to 50% in disk space, so you may well find that you can install 30 - 35 3 " disks on the 590, which should take care of most of your important programs. Programs such as Professional Page and WordPerfect with its dictionary and thesaurus and compilers such as Lattice C are far easier to use on a hard drive. On a 20 Meg drive one could install the maximum amount of program disks and save some data to 3 " disks; however you may well decide to have a smaller range of programs on the 590 and save your data as well to the hard drive. Chacun a son gout! [Ed: rough translation: each one gets gout when a hard disk crashes.] The A590 turns the 500 into quite a powerful computer. It is the logical extension for users who have outgrown the 'standard' 500. If it turns out to be a commercial success, we would not be at all surprised if Commodore would in due course release one or more alternative versions with different capacity hard drives. Third party suppliers should also be able to supply larger capacity drives without difficulty, depending on your wallet! We can see one major problem for Commodore when they release this unit. What are they going to do with all those A2000s that will end up gathering dust in the back of the warehouse! The only regret is that after using this nice little unit for some days we have to return it. Once you have used a hard drive on the Amiga, life is simply impossible without one!