For the Commodore 64 & 128 Computers

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DOS Commands


Logical Unit ACTIVATION:

If you installed a new drive and either used the LU default settings or made changes to the size of LUs, you must now 'Activate' each LU (Yes, if you created 10 user LUs, you need to Activate each of the 10 LUs)! During CONFIG, all that happened was the Cylinder (Sector) allocation was divided up into a number of LUs. Just like partitioning a hard drive on a PC, you need to create an INDEX and bitmap (BAM) for each LU. The way this is done on the Lt. Kernal is to run the ACTIVATE command.

When you run the Activate command on a Configured new hard drive, you'll do so from LU 10. After you've installed SYSGEN and CONFIGured some user LUs, you do a complete reset and powered up the Commodore again. At this point, the only LU that was automatically Configured and Activated was the DOS LU - LU 10. Therefore, when you run the Activate command, you'll do so for each LU you created in the Configure step.

So, enter 'activate' and press Enter (Like all DOS commands, the name is simply entered, in lowercase, on the far-left column and then press Enter.) The first thing the Activate command wants to know is which LU number do you want to create (e.g. LU 0). You'll then be told that 'activating' the LU will erase all data on the logical unit and ask for a Y/N response to continue. If you enter Y, you should notice two things:

  • On a new screen, a number of star symbols (*) start printing from left to right on the top line of the screen. Not well known or understood, the number of stars represents the SIZE of the LU. That is, if you are 'activating' a default LU 0 on a small capacity drive, you may see 5 to 10 stars. However, if you have set the LU to its' Maximum capacity (number of Cylinders which represents 65,000 Blocks), the entire 40-column top line and part of the second line may fill with stars! This is particularly important when visually verifying that LK DOS and the HARD DRIVE understand the Size of the LU.
  • After the star symbols finish printing, the period (.) symbol will continue printing 1 or 6 Rows of characters which represents that it is erasing the LU.

When Activation is complete, you are asked if you want to install an 'image' of DOS (from LU 10) onto the LU number you just Activated. The purpose of this DOS 'image' (or copy of all DOS) was meant to speedup DOS execution. Well, when using the Mother of all Slow drives (Miniscribe 8425S), putting a copy of DOS on other LUs did speedup execution times because the commands are fetched from LU 10. That is, the further the physical distance from LU 10 and the LU from which you requested the command, the longer it takes to fetch the DOS (seek times). However, if you are using any 'reasonably fast' drive, installing the DOS image on any LU will not noticeably speedup file loading times. However, if you configure two or more hard drives, the SCSI ID# 1 (or higher) drive will have to go to the SCSI ID#0 drive for DOS. And, if you use three hard drives and the first drive (SCSI ID#0) is the slowest drive, installing DOS images on the other two drives is an excellent way to make use of the slow drive! (It's the best way to make use of the original/stock 20 meg Miniscribe without slowing down the other two drives!)

Furthermore, running the 'updatedos' command will automatically refresh All DOS images (should they become corrupted) if they were previously install on an LU (even on another hard drive). So, why not? DOS images don't take up that much space and DOS loading times May be improved. When I build a new system and use multiple drives, I always install a DOS image on All LUs (normally all 10 User LUs).

Once the LU has been Activated, it's ready for use and files may be stored on and retrieved from that LU only. Therefore, you need to Activate All of your defined LUs. When you exit Activation, you are returned to a blinking cursor with no status line. To view the LU you have just activated, enter that LU number on the far-left column (e.g., LU 0) and hit Enter. For a C64, you should now see the following (unless you changed the default Drive# and USER# in CONFIG):

C64 D#08 LU00 USER00 PORT#00

Now enter the command 'DIR' and you'll see all of the files currently on LU 00. On a new drive, you should see the DISCBITMAP, SYSTEMINDEX and DOS image file (if you installed it). You will also see how many Blocks are still available and how many Blocks are used, including how much the Discbitmap and DOS individually use.

The 'Blocks available' represents the actual space you have for storage. However, a HARD DRIVE Block is 512 Bytes in size compared to a Commodore Block size of 256 Bytes. Therefore, if you store a Commodore file which is, say, 100 blocks, you will see that the same file on the Lt. Kernal only uses 50 Hard Drive Blocks. Keep this block-size difference in mind before you assume that the file is corrupt or bad! This also means that if you set the LU size to '65K' Blocks, you actually have 130,000 Commodore Blocks of storage on just that one LU (e.g., 33 Meg).

USER subdirectories:

Within each LU, you can divide your file storage into different USER areas (up to 16). This does not require editing of your CONFIG file. To use an USER area, first select its Number. At the prompt line, enter USER 14, hit Enter, and you'll now be in the USER 14 area. If you type in the DIR command, the only files you'll see are the ones that were placed in that LU & USER number. Unlike UNIX or MS-DOS, there's no file system hierarchy in the Lt. Kernal; merely an user area scheme that corresponds to CP/M storage. In fact, the user area number is pre-pended to the disk directory entry and routines that search the directory use the current user area as part of the search pattern (even if no pattern is specified, the user area is implied. Furthermore, if you wanted to open a file in BASIC, you could say OPEN(2,8,2)"0:3:filename", which would open a file that was on LU 0, USER 3.

Taking advantage of the USER function is a great way of saving copies or backup files. For example, you could setup an LU 04 during CONFIG just for backups. Within LU 04, you could then place LU 00 backup files in LU 04, USER 00; LU 01 backup files in LU 04, USER 01, and so on. There is no limit on how (or if) the USER capability is utilized.

Note: Keep in mind that you can only store 4,000 files per LU (i.e., not 4K files in each USER # per LU#). Again, the reason for this is because the USER function is merely a directory entry scheme, which adds the USER number to the file name.

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