dwl10@amdahl.amdahl.com (Dave Lowrey) (09/10/87)
I just purchased a Commodore 1581 disk drive for my C64. I thought
folks out in netland would be interested in a review....
Physical:
The drive is small (63mm high, 140mm wide, and 230mm deep), with an
external 10 watt power supply. It uses "Any good quality 3.5 inch
double sided diskettes"(quote). I bought a box of Memorex single
sided quad density disks (the only type in the store) and those
work, but I plan on buying true double sided disks in the future.
After formatting, a disk has 3160 free 256k blocks avaliable for storage.
Logically, a disk has 80 tracks, of 40 sectors each. The directory
track is on track 40. Three sectors of track 40 are used for the disk
header and 2 BAMs, which leaves 37 directory blocks. This yeilds a
maximum of 296 files per disk (excluding partitioning, see below).
Sequential files can contain up to 802,640 bytes. Relative files
can be up to (approx.)800K with a maximum of 65535 records/file.
For those interested: The disk actually has 80 cylinders, 2 tracks (sides)
per cylinder. Each track contains 10 512 byte sectors. The drive
translate the logical mapping to the physical and vice versa. This
allows (theoretically) the drive to read disks created for other
machines (mac & pc), as it can be set to read other block sizes.
Interface:
The drives uses the standard CBM serial interface. It has external
dip switches to set the device's address to 8,9,10, or 11. The
drive recognizes the "standard" CBM disk commands to open, read,
write, etc. There are also a set of "burst" commands for reading
the disk in it's native mode(s). Access times are bit faster than
a standard 1541, because the drive buffers a whole track at a time, so
subsequent access to sectors on the same track require no disk
seek and access time. This makes directory searches MUCH faster,
and sequential read/writes and saves/loads appear to be about
1/3 faster (very unscientific measuring). However, as would be
expected, my fastload cart. doesn't work with the drive when
trying to load.
Partitioning:
The 1581 introduces a new feature called partitioning. This feature
allows you to designate a particular area on the disk as being protected,
as if a file resided there. Thus, the Validate command will not
reclaim any of the blocks in the partitioned off area. For those of
you who do direct access programming, this is a big help.
The real benifit of partitions is that you can create a new 'virtual
disk' within a partition, complete with directory and BAM. You can then
create a new partition within a partition, etc. This somewhat
resembles the UNIX file system structures. There are limitations however.
You can only access files in the "current" partition. You can change the
current partition to be one of the partitions in the current directory,
but to go back "up" the tree, you first must go all the way back to
"root' (/) and go down to the desired partition. I plan to use this
feature to keep my C-Power sources straight. I can have one disk for
all of my sources, but each group of programs will be in it's own
partition. A partition is listed as file type "CBM" in a directory.
Software:
The drive comes with a TEST/DEMO disk containing many programs. Most are
newer versions of the standard CBM disk stuff. However there is a very
nice sector editor that works with all types of CBM drives. Also
are samples of code using Burst mode (128 only), a partitioning
aid, and several different disk copy programs.
Documentation:
The documentation is fairly good. It describes all of the disk
commands (scratch, rename, load, save, etc.) and how to do them with
both BASIC 2.0 (C64) and BASIC 7.0 (128). It then goes on to give
programming info for Sequential files, Relative files, Direct access,
and Internal disk commands (memory read, memory write, etc). Next,
the format of the Burst commands is describes. There aren't any examples
in this section, so it can be a bit confusing. Finally, there is a
"internals" section, complete with a DOS memory map, a description of
the controller job queue, and a description of the vectored jump
table. A set of appendices describe changing device numbers, dos error
messages, disk command qwick reference, 1581 specs, and serial bus
information.
Impressions:
- The biggest drawback to the drive is loosing the fastload ability. So,
I will use the drive for data storage, but not many programs.
- I would also like to see a fast copy program. I calculate a full
disk backup time of 45-60 mins (not including floppy disk swaps!).
- Altho the disk is much larger, the still havn't increased the number
of buffers in the drive (excluding the whole track buffer). Therfore,
you still have the same limits on the number of open files.
- There isn't any support (yet) for the 1581 in GEOS-64.
Questions: (Listen up Commodore :-) )
1. Can burst mode be used on the 64? If so, is there a "fast" serial bus
driver avaliable?
2. The burst mode source file on my demo disk is trashed. I tried to
print it, and after 5 or 6 pages, the file is garbage. Is it just my
disk, or are all of them that way? If it is just my disk, can I get
a new one? If they are all that way, can I get ahold of a good copy?
3. There is a program on the disk called zapload.64. It includes a
fast loader that works with all CBM drives. Can I get ahold of the
source to this program? (I know, get the ol' disassembler out, right?)
4. The drive has the capability of automatically loading a file
into one of it's buffers, and executing that program upon
drive initialization. This is documented in the 1581 manual. I
know that this feature was also on the 1541, but undocumented.
My question is... what the heck good is it? What would you
use it for? I am making the rash assumption that it is there for
a purpose.
5. Is "save with replace" safe to use with the 1581?
6. Are there any known bugs with the drive?
Final Words:
I bought this drive for it's storage capacity. The faster sequential/
relative file access is a plus also. The drive seems to meet all of
my expectations on those points. I sorely miss the fastload capabilities,
but I expected that when I bought the drive. The drive delivers what
it promises, and I would recomend it to anyone needing a large amount
of storage capacity.
--
-------------------------------------------------------------------
"Familiarity breeds attempt"
Dave Lowrey
Amdahl Corp.
Houston, Texas
(713)-850-8828
...!{ihnp4,cbosgd,hplabs,oliveb}!amdahl!dwl10
[ The opinions expressed <may> be those of the author and not necessarily
those of his most eminent employer. ]ahh@s.cc.purdue.edu (Brent L. Woods) (09/11/87)
In article <14031@amdahl.amdahl.com> dwl10@amdahl.amdahl.com (Dave Lowrey) writes: > >Questions: (Listen up Commodore :-) ) > 1. Can burst mode be used on the 64? If so, is there a "fast" serial bus > driver avaliable? No, it can't. Also, fast serial is only available on the 128 in C128 mode. If you put the 128 into 64 mode, it can't do fast serial, either. > 2. The burst mode source file on my demo disk is trashed. I tried to > print it, and after 5 or 6 pages, the file is garbage. Is it just my > disk, or are all of them that way? If it is just my disk, can I get > a new one? If they are all that way, can I get ahold of a good copy? Mine is just fine (works pretty good, too). I bought my 1581 about three and a half weeks ago. > 4. The drive has the capability of automatically loading a file > into one of it's buffers, and executing that program upon > drive initialization. This is documented in the 1581 manual. I > know that this feature was also on the 1541, but undocumented. > My question is... what the heck good is it? What would you > use it for? I am making the rash assumption that it is there for > a purpose. Yes, I would think so. One good use that comes to mind is re- configuring the drive on startup. My roommate has an Amiga, and I'm planning on writing a program to allow my 128 and his Amiga to trade files via 3.5" disks. > 5. Is "save with replace" safe to use with the 1581? Supposedly, that bug has been killed. The real question is, "Do you want to take the chance?" > 6. Are there any known bugs with the drive? Not yet... :-) >Final Words: > I bought this drive for it's storage capacity. The faster sequential/ > relative file access is a plus also. The drive seems to meet all of > my expectations on those points. I sorely miss the fastload capabilities, Gee, I don't have any problem with slow loading... But, I have a 128, so I get to use the fast serial bus. The 1581 is my second drive, and I find that it complements my 1571 *very* nicely. I don't use any form of fastload, program or cartridge, and I haven't noticed any loss. > but I expected that when I bought the drive. The drive delivers what > it promises, and I would recomend it to anyone needing a large amount > of storage capacity. -Brent Woods
fred@cbmvax.UUCP (Fred Bowen) (09/11/87)
dwl10@amdahl.amdahl.com (Dave Lowrey) reviews the CBM 1581 disk drive: > ... It uses "Any good quality 3.5 inch > double sided diskettes"(quote). I bought a box of Memorex single > sided quad density disks (the only type in the store) and those > work, but I plan on buying true double sided disks in the future. Gads. DS/DD soft sector (135 TPI). I fear a lot of problems I hear about (which I cannot duplicate, natch) are caused by things like this. Expect problems if you do this. For some reason quite a few 1541 folks, used to 160K on 5.25" media, don't understand what it takes to put >800K on 3.5" media. > - The biggest drawback to the drive is loosing the fastload ability. So, > I will use the drive for data storage, but not many programs. > - I would also like to see a fast copy program. I calculate a full > disk backup time of 45-60 mins (not including floppy disk swaps!). Please note, this is 'slow' protocol on a c64. You really should try loading a hugh program on a c128/1581. Nice. > Questions: (Listen up Commodore :-) ) > 1. Can burst mode be used on the 64? If so, is there a "fast" serial bus > driver avaliable? Nope- requires some hardware mods. But I'm sure someone will come up with a hardware thingy to accomplish this before much longer. A fast serial add-on cartridge or some such. > 2. The burst mode source file on my demo disk is trashed. I tried to > print it, and after 5 or 6 pages, the file is garbage. Is it just my > disk, or are all of them that way? If it is just my disk, can I get > a new one? If they are all that way, can I get ahold of a good copy? > 3. There is a program on the disk called zapload.64. It includes a > fast loader that works with all CBM drives. Can I get ahold of the > source to this program? (I know, get the ol' disassembler out, right?) Your disk is probably bad- if you bought the drive from a dealer (as opposed to Toys R something) you could probably exchange it. That or find a friend. The source for the Burst routines, ZAPLOADER, etc. are also gonna appear on the DEVpak disk collection (mostly for c128 folks). > 4. The drive has the capability of automatically loading a file > into one of it's buffers, and executing that program upon > drive initialization. This is documented in the 1581 manual. I > know that this feature was also on the 1541, but undocumented. > My question is... what the heck good is it? What would you > use it for? I am making the rash assumption that it is there for > a purpose. Yup- the autobooter is similar to the good old utility file loader, it just loads & runs a specific file into DOS RAM whenever the drive is initialized. It is used, for example, by c128 CP/M boots (to download a different logical sector map). It is useful. > 5. Is "save with replace" safe to use with the 1581? Yup. But I ain't no fool- I still scratch n' save. > 6. Are there any known bugs with the drive? 2 very minor ones that I know of so far- following some writes immediately (less than 250ms) with a UJ (soft reset) to the command channel will cause the drive not to dump the 'dirty' track cache to disk before resetting. The other is a BURST command will cause any direct access channels (#) to disappear (who mixes BURST stuff with # stuff anyway? This is easily worked around anyhow). > Final Words: > I bought this drive for it's storage capacity. The faster sequential/ > relative file access is a plus also. The drive seems to meet all of > my expectations on those points. I sorely miss the fastload capabilities, > but I expected that when I bought the drive. The drive delivers what > it promises, and I would recomend it to anyone needing a large amount > of storage capacity. Thanks, Dave. Transactor has a review this month which basically says the same things as you did. -- -- Fred Bowen uucp: {ihnp4|rutgers|caip}!cbmvax!fred arpa: beats me tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380
kev@voder.UUCP (Kevin Hoskins) (09/18/87)
In article <733@uokmax.UUCP>, rufsmith@uokmax.UUCP (Russell F Smith) writes: > In article <927@s.cc.purdue.edu> ahh@s.cc.purdue.edu.UUCP (Brent L. Woods) writes: > >In article <14031@amdahl.amdahl.com> dwl10@amdahl.amdahl.com (Dave Lowrey) writes: > > > > > > 4. The drive has the capability of automatically loading a file > > > into one of it's buffers, and executing that program upon > > > drive initialization.... I know that this feature was also > > > on the 1541, but undocumented.... > > .... > > > .... Could someone please give me a deeper rundown on the feature, as > I own a 1541? I am > always looking for undocumented info on it ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > (there are quite a few things, you know) and this one seems right ^^^^^^^^^^^^^^^^^^ > up my alley.... If you, or anyone else out there would share these undocumented features with the rest of us, I can assure you that we would be most grateful. In fact undocumented features of the entire Commodore line and GEOS operating system and applications would make for very interesting reading and usefulness in using the software. Thanks, Kevin
lishka@uwslh.UUCP (Christopher Lishka) (09/19/87)
In regards to the reader who was looking for undocumented features, I
would like to persuade anyone out there who knows of useful,
undocumented commands, quirks, and what-have-you's to please post a
message so that others can find out. If there are too many, post a
summary, or give references of good books which would explain the
undocumeneted phenomena. I, and I assume many others, would really
enjoy finding out about some good things present in the c64 and 1541
that I don't already know.
-Chris
--
Chris Lishka /lishka@uwslh.uucp
Wisconsin State Lab of Hygiene <-lishka%uwslh.uucp@rsch.wisc.edu
\{seismo, harvard,topaz,...}!uwvax!uwslh!lishkafred@cbmvax.UUCP (Fred Bowen) (09/21/87)
This is a re-posting of something I originally posted last Friday after a system crash- the system date was fubar, and you may not have seen it. > > > 4. The drive has the capability of automatically loading a file > > > into one of it's buffers, and executing that program upon > > > drive initialization. This is documented in the 1581 manual. I > > > know that this feature was also on the 1541, but undocumented. Yes, the 1581 has an "autoload" feature, based upon the utility loader feature that is found in the 1571 (lookup "utility loader" in the index). The utility load feature is not found on the 1541, although the whole scheme is based upon USR type files which, of course, do exist on the 1541. On the 1571, USR type files can be loaded into DOS memory via the "&" command ( OPEN1,8,15,"&0:FOO" ). The 1581 carries this one step further by adding an "autoload" feature- if the USR filename is COPYRIGHT CBM 86 then, upon drive initialization (e.g., turn it on with disk installed, or send via the command channel an "I" or "UJ", Burst Query, or Burst Inquire) that file will automatically be loaded into DOS RAM *and* executed. Hope this helps- the various manuals do explain this stuff pretty well. I'll be glad to go into this further if you are still interested... -- -- Fred Bowen uucp: {ihnp4|rutgers|caip}!cbmvax!fred arpa: beats me tele: 215 431-9100 Commodore Electronics, Ltd., 1200 Wilson Drive, West Chester, PA, 19380