RL02 version of UNIX6?

John Forecast john at forecast.name
Mon Feb 6 10:08:20 CST 2017

> On Feb 6, 2017, at 8:35 AM, william degnan <billdegnan at gmail.com> wrote:
>>> Mark and John,
>>> Summarizing...The disks in the RL01 directory are 5MB, which is the RL01
>>> disk size I believed, but if they are RL02, why would I not use "RL02" in
>>> the simh commands?
>>> For example the code Mark wrote with John's changes, should it not be
>> rlo2,
>>> not rl01?
>>> sim> sho cpu
>>> CPU     11/40, idle enabled, autoconfiguration enabled
>>>       64KB
>>> sim> sh rl
>>> RL      RL11, address=17774400-17774411, vector=160, 4 units
>>> RL0   2621KW, attached to rsxm32.rl01, on line
>>>       write enabled, RL01
>>> RL1   2621KW, attached to excprv.rl01, on line
>>>       write enabled, RL01
>>> RL2   2621KW, attached to mcrsrc.rl01, on lineBRU (Backup and restore
>>>       write enabled, RL01
>>> RL3   2621KW, attached to rlutil.rl01, on line
>>>       write enabled, RL01
>>> sim> b rl
>>        The v3.2 version I have from bitsavers has the baseline disk a few
>> bytes larger than
>>        an RL01 so simH autosized it (incorrectly) to an RL02. Hopefully
>> Mark’s new sizing
>>        code should avoid this in the future. To copy an RL01 RSX disk to
>> an RL02 you can use
>>        BRU (Backup and Restore Utility). Get the magtape image
>>        BB-L974F-BC_RSX11M_4.5_BRU64K.tap from bitsavers. Attach your
>> RL01 image to
>>        rl0 and create a new RL02 image attached to rl1. Boot the magtape:
>>        first device is dl0:
>>        second device is dl1:
>>        At the “>” prompt type “run bru”
>>        At the “BRU>” prompt type “/init dl0: dl1:” and it will perform
>> the copy. If you copied the
>>        baseline system, you should be able to boot the newly created RL02.
>>  John.
> So essentially what you're saying is that simH by luck converted the disk
> to RL02 because it was converted to disk format incorrectly, and that at
> some point the disk image ballooned to 10MB from 5MB? Above you see the
> output of
> simh> sh rl
> ...after the re-sizing of the disk, would this config fail to be able to
> load the disks because they were resized?  At some point these RL01's were
> changed to RL02s?  Or can you with simH  simply load an RL02 disk even
> though you set the rl = RL01?  See what I mean?
> Bill

	simH did not change the size of the disk image. By default, simH will automatically
	detect the type of disk on a particular controller (e.g. RL01/RL02, RK06/RK07) based
	on the size of the disk image. When I attached the image and did a”sh rl0” it showed up
	as an RL02 - those extra few bytes made the difference. The RSX distribution kit I
	have is probably from a different source. Later testing showed that I could copy the
	baseline disk to an RL02 using standalone BRU but I was unable to do the copy using
	standalone DSC (an earlier backup program).

	I just checked the current simH source and, if autosize is enabled, it treats any image file
	larger than an RL01 as an RL02. If you turn off autosizing and set the drive to RL01, it
	will always consider it an RL01, regardless of the actual size. Any attempt to read/write
	past 5MB will return an error.


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