Purpose of two disk drives on the Osborne 1











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I recently discovered the Osborne 1 computer, and I noticed it had two floppy disc drives.



What was the purpose of including two drives?










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  • 1




    It didn't. It had 2 drives and 2 slots for storage. If you zoom in the pictures you will see that the lower holes just are storage slots.
    – UncleBod
    12 hours ago












  • @UncleBod - I see. Corrected!
    – QueenSvetlana
    12 hours ago












  • @UncleBod - Still, why provide more than one disk drive? What was the purpose, for copying? Was it possible to load data off of two drives at the same time?
    – QueenSvetlana
    12 hours ago















up vote
4
down vote

favorite












I recently discovered the Osborne 1 computer, and I noticed it had two floppy disc drives.



What was the purpose of including two drives?










share|improve this question









New contributor




QueenSvetlana is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 1




    It didn't. It had 2 drives and 2 slots for storage. If you zoom in the pictures you will see that the lower holes just are storage slots.
    – UncleBod
    12 hours ago












  • @UncleBod - I see. Corrected!
    – QueenSvetlana
    12 hours ago












  • @UncleBod - Still, why provide more than one disk drive? What was the purpose, for copying? Was it possible to load data off of two drives at the same time?
    – QueenSvetlana
    12 hours ago













up vote
4
down vote

favorite









up vote
4
down vote

favorite











I recently discovered the Osborne 1 computer, and I noticed it had two floppy disc drives.



What was the purpose of including two drives?










share|improve this question









New contributor




QueenSvetlana is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











I recently discovered the Osborne 1 computer, and I noticed it had two floppy disc drives.



What was the purpose of including two drives?







hardware floppy-disk






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QueenSvetlana is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









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edited 3 hours ago









paxdiablo

1,5961235




1,5961235






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asked 12 hours ago









QueenSvetlana

233




233




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QueenSvetlana is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






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Check out our Code of Conduct.








  • 1




    It didn't. It had 2 drives and 2 slots for storage. If you zoom in the pictures you will see that the lower holes just are storage slots.
    – UncleBod
    12 hours ago












  • @UncleBod - I see. Corrected!
    – QueenSvetlana
    12 hours ago












  • @UncleBod - Still, why provide more than one disk drive? What was the purpose, for copying? Was it possible to load data off of two drives at the same time?
    – QueenSvetlana
    12 hours ago














  • 1




    It didn't. It had 2 drives and 2 slots for storage. If you zoom in the pictures you will see that the lower holes just are storage slots.
    – UncleBod
    12 hours ago












  • @UncleBod - I see. Corrected!
    – QueenSvetlana
    12 hours ago












  • @UncleBod - Still, why provide more than one disk drive? What was the purpose, for copying? Was it possible to load data off of two drives at the same time?
    – QueenSvetlana
    12 hours ago








1




1




It didn't. It had 2 drives and 2 slots for storage. If you zoom in the pictures you will see that the lower holes just are storage slots.
– UncleBod
12 hours ago






It didn't. It had 2 drives and 2 slots for storage. If you zoom in the pictures you will see that the lower holes just are storage slots.
– UncleBod
12 hours ago














@UncleBod - I see. Corrected!
– QueenSvetlana
12 hours ago






@UncleBod - I see. Corrected!
– QueenSvetlana
12 hours ago














@UncleBod - Still, why provide more than one disk drive? What was the purpose, for copying? Was it possible to load data off of two drives at the same time?
– QueenSvetlana
12 hours ago




@UncleBod - Still, why provide more than one disk drive? What was the purpose, for copying? Was it possible to load data off of two drives at the same time?
– QueenSvetlana
12 hours ago










4 Answers
4






active

oldest

votes

















up vote
12
down vote



accepted










Remember that these systems (not only the Osborne 1) didn't have harddisks. Everything ran from floppies.



So usually you had one floppy where the program was on, together with OS related files. And another floppy for your data, texts and so on.



That was workable with two drives, but still was impractical if you wanted to copy data. Usually there was some way to load a program and then use the first drive for a second data disk while doing the copying, but then you had to re-insert the system disk etc. So a third drive wouldn't have been too bad (but few systems had one).



TL;DR: You could never have enough floppy drives. Working with one floppy drive was a pain sometimes because you often had to switch disks; working with two was enough for most cases; and sometimes more than two would have been nice.



The same was true for other systems like the DEC PDP-8, which used DEC tapes pretty much the same way floppies were used on CP/M systems. And there were tape controllers which allowed for four tape drives. This was there for a reason...






share|improve this answer





















  • I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
    – Brian H
    7 hours ago


















up vote
2
down vote













Note CP/M (the Operating system of the Osborne) didn't have subdirectories as we know today (which more or less forced you to dedicate a disk for a specific purpose in order to keep the overview), it also had very limited storage capacity per disk drive (~180k on a SS/SD disk as on the Osborne 1).



That means you typically held the application (for example WordStar, with a typical disk footprint of ~50-60kBytes) on one drive on a write-protected disk (in case it had to load overlays or messages) and the actual text you were working on on a disk in the other drive (the working disk). If you didn't want to be forced to constantly swap disks, you also put the operating system files on your program disk which also took some of the capacity.



You could have worked with only one drive, but that was much more cumbersome and carried the risk of destroying your program disk (because that could not be write-protected, then) or you had to change disks occasionally.



Obviously copying between disks was much simpler with a 2-drive setup, as others have mentioned.






share|improve this answer























  • Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
    – Brian
    6 hours ago










  • From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
    – supercat
    5 hours ago










  • @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
    – tofro
    5 hours ago




















up vote
1
down vote













The Osborne 1, like many computers of the time, had no means of data storage other than floppy disks. On powering up, the user would be prompted to insert the operating system disk, so the machine could boot.



Even when running other software, the computer would need to access and run parts of the OS periodically. If you only had one floppy drive, you'd have to continuously eject and insert the OS disk and your data disk when running some commands. It was far more desirable to have two drives available, so the OS disk could be left in one drive for most of the time.



Having two floppy drives also speeds up copying files between different disks, but this is a secondary benefit.



The provision of two floppy drives was also common with other machines, such as the IBM PC and the BBC Micro (though the latter had its OS in a ROM on the motherboard). When hard drives were installed in computers, the OS could be installed there, and there was no longer such a benefit from having a second floppy drive.






share|improve this answer





















  • Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
    – supercat
    12 hours ago










  • @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
    – alephzero
    11 hours ago












  • @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
    – supercat
    11 hours ago




















up vote
0
down vote













Since the computer only has disk drives and no hard-disk, the normal usage was to have the system programs and a word processor or database handler on one diskette and using the other for data or documents.
Those drives were single side, single density as standard, which gave a storage capacity of somewhere around 100 kBytes each.






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    4 Answers
    4






    active

    oldest

    votes








    4 Answers
    4






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    12
    down vote



    accepted










    Remember that these systems (not only the Osborne 1) didn't have harddisks. Everything ran from floppies.



    So usually you had one floppy where the program was on, together with OS related files. And another floppy for your data, texts and so on.



    That was workable with two drives, but still was impractical if you wanted to copy data. Usually there was some way to load a program and then use the first drive for a second data disk while doing the copying, but then you had to re-insert the system disk etc. So a third drive wouldn't have been too bad (but few systems had one).



    TL;DR: You could never have enough floppy drives. Working with one floppy drive was a pain sometimes because you often had to switch disks; working with two was enough for most cases; and sometimes more than two would have been nice.



    The same was true for other systems like the DEC PDP-8, which used DEC tapes pretty much the same way floppies were used on CP/M systems. And there were tape controllers which allowed for four tape drives. This was there for a reason...






    share|improve this answer





















    • I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
      – Brian H
      7 hours ago















    up vote
    12
    down vote



    accepted










    Remember that these systems (not only the Osborne 1) didn't have harddisks. Everything ran from floppies.



    So usually you had one floppy where the program was on, together with OS related files. And another floppy for your data, texts and so on.



    That was workable with two drives, but still was impractical if you wanted to copy data. Usually there was some way to load a program and then use the first drive for a second data disk while doing the copying, but then you had to re-insert the system disk etc. So a third drive wouldn't have been too bad (but few systems had one).



    TL;DR: You could never have enough floppy drives. Working with one floppy drive was a pain sometimes because you often had to switch disks; working with two was enough for most cases; and sometimes more than two would have been nice.



    The same was true for other systems like the DEC PDP-8, which used DEC tapes pretty much the same way floppies were used on CP/M systems. And there were tape controllers which allowed for four tape drives. This was there for a reason...






    share|improve this answer





















    • I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
      – Brian H
      7 hours ago













    up vote
    12
    down vote



    accepted







    up vote
    12
    down vote



    accepted






    Remember that these systems (not only the Osborne 1) didn't have harddisks. Everything ran from floppies.



    So usually you had one floppy where the program was on, together with OS related files. And another floppy for your data, texts and so on.



    That was workable with two drives, but still was impractical if you wanted to copy data. Usually there was some way to load a program and then use the first drive for a second data disk while doing the copying, but then you had to re-insert the system disk etc. So a third drive wouldn't have been too bad (but few systems had one).



    TL;DR: You could never have enough floppy drives. Working with one floppy drive was a pain sometimes because you often had to switch disks; working with two was enough for most cases; and sometimes more than two would have been nice.



    The same was true for other systems like the DEC PDP-8, which used DEC tapes pretty much the same way floppies were used on CP/M systems. And there were tape controllers which allowed for four tape drives. This was there for a reason...






    share|improve this answer












    Remember that these systems (not only the Osborne 1) didn't have harddisks. Everything ran from floppies.



    So usually you had one floppy where the program was on, together with OS related files. And another floppy for your data, texts and so on.



    That was workable with two drives, but still was impractical if you wanted to copy data. Usually there was some way to load a program and then use the first drive for a second data disk while doing the copying, but then you had to re-insert the system disk etc. So a third drive wouldn't have been too bad (but few systems had one).



    TL;DR: You could never have enough floppy drives. Working with one floppy drive was a pain sometimes because you often had to switch disks; working with two was enough for most cases; and sometimes more than two would have been nice.



    The same was true for other systems like the DEC PDP-8, which used DEC tapes pretty much the same way floppies were used on CP/M systems. And there were tape controllers which allowed for four tape drives. This was there for a reason...







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 12 hours ago









    dirkt

    8,59312346




    8,59312346












    • I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
      – Brian H
      7 hours ago


















    • I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
      – Brian H
      7 hours ago
















    I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
    – Brian H
    7 hours ago




    I'd say the same thing is true for any floppy-based micro I've ever used. You needed two floppy drives for usability either as a boot disk+data disk setup, or for when you were making backups. One disk floppy systems were far less convenient for real work, but fine if you just booted games.
    – Brian H
    7 hours ago










    up vote
    2
    down vote













    Note CP/M (the Operating system of the Osborne) didn't have subdirectories as we know today (which more or less forced you to dedicate a disk for a specific purpose in order to keep the overview), it also had very limited storage capacity per disk drive (~180k on a SS/SD disk as on the Osborne 1).



    That means you typically held the application (for example WordStar, with a typical disk footprint of ~50-60kBytes) on one drive on a write-protected disk (in case it had to load overlays or messages) and the actual text you were working on on a disk in the other drive (the working disk). If you didn't want to be forced to constantly swap disks, you also put the operating system files on your program disk which also took some of the capacity.



    You could have worked with only one drive, but that was much more cumbersome and carried the risk of destroying your program disk (because that could not be write-protected, then) or you had to change disks occasionally.



    Obviously copying between disks was much simpler with a 2-drive setup, as others have mentioned.






    share|improve this answer























    • Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
      – Brian
      6 hours ago










    • From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
      – supercat
      5 hours ago










    • @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
      – tofro
      5 hours ago

















    up vote
    2
    down vote













    Note CP/M (the Operating system of the Osborne) didn't have subdirectories as we know today (which more or less forced you to dedicate a disk for a specific purpose in order to keep the overview), it also had very limited storage capacity per disk drive (~180k on a SS/SD disk as on the Osborne 1).



    That means you typically held the application (for example WordStar, with a typical disk footprint of ~50-60kBytes) on one drive on a write-protected disk (in case it had to load overlays or messages) and the actual text you were working on on a disk in the other drive (the working disk). If you didn't want to be forced to constantly swap disks, you also put the operating system files on your program disk which also took some of the capacity.



    You could have worked with only one drive, but that was much more cumbersome and carried the risk of destroying your program disk (because that could not be write-protected, then) or you had to change disks occasionally.



    Obviously copying between disks was much simpler with a 2-drive setup, as others have mentioned.






    share|improve this answer























    • Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
      – Brian
      6 hours ago










    • From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
      – supercat
      5 hours ago










    • @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
      – tofro
      5 hours ago















    up vote
    2
    down vote










    up vote
    2
    down vote









    Note CP/M (the Operating system of the Osborne) didn't have subdirectories as we know today (which more or less forced you to dedicate a disk for a specific purpose in order to keep the overview), it also had very limited storage capacity per disk drive (~180k on a SS/SD disk as on the Osborne 1).



    That means you typically held the application (for example WordStar, with a typical disk footprint of ~50-60kBytes) on one drive on a write-protected disk (in case it had to load overlays or messages) and the actual text you were working on on a disk in the other drive (the working disk). If you didn't want to be forced to constantly swap disks, you also put the operating system files on your program disk which also took some of the capacity.



    You could have worked with only one drive, but that was much more cumbersome and carried the risk of destroying your program disk (because that could not be write-protected, then) or you had to change disks occasionally.



    Obviously copying between disks was much simpler with a 2-drive setup, as others have mentioned.






    share|improve this answer














    Note CP/M (the Operating system of the Osborne) didn't have subdirectories as we know today (which more or less forced you to dedicate a disk for a specific purpose in order to keep the overview), it also had very limited storage capacity per disk drive (~180k on a SS/SD disk as on the Osborne 1).



    That means you typically held the application (for example WordStar, with a typical disk footprint of ~50-60kBytes) on one drive on a write-protected disk (in case it had to load overlays or messages) and the actual text you were working on on a disk in the other drive (the working disk). If you didn't want to be forced to constantly swap disks, you also put the operating system files on your program disk which also took some of the capacity.



    You could have worked with only one drive, but that was much more cumbersome and carried the risk of destroying your program disk (because that could not be write-protected, then) or you had to change disks occasionally.



    Obviously copying between disks was much simpler with a 2-drive setup, as others have mentioned.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 11 hours ago

























    answered 11 hours ago









    tofro

    14.2k32980




    14.2k32980












    • Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
      – Brian
      6 hours ago










    • From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
      – supercat
      5 hours ago










    • @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
      – tofro
      5 hours ago




















    • Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
      – Brian
      6 hours ago










    • From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
      – supercat
      5 hours ago










    • @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
      – tofro
      5 hours ago


















    Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
    – Brian
    6 hours ago




    Starting with CP/M 2.2, which I believe the Osborne I shipped with, it did have 16 user areas per disk so you could split up files and use user 1 etc to switch between user areas.
    – Brian
    6 hours ago












    From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
    – supercat
    5 hours ago




    From what i understand, the user areas were similar to folders in MacOs 1.0; all files were stored in the same directory, but the user area number (or folder number) was treated as part of the name, so the within user areas 2 and 3, "foo.txt" would behave like "2foo.txt" or "3foo.txt", respectively. While write protecting master program disks would have been desirable, not all programs could usefully run from write-protected disks. The CP/M equivalent of batch files, for example, required the ability to write to the startup disk.
    – supercat
    5 hours ago












    @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
    – tofro
    5 hours ago






    @brian Right, but: On a 180k disk, user areas are not particularly useful - It doesn't make the disk space any larger. Many people didn't use user areas anyhow: they were more of a nuisance than useful because they simply hide files completely, and PIP.COM must be present in each user area you want to copy files into.
    – tofro
    5 hours ago












    up vote
    1
    down vote













    The Osborne 1, like many computers of the time, had no means of data storage other than floppy disks. On powering up, the user would be prompted to insert the operating system disk, so the machine could boot.



    Even when running other software, the computer would need to access and run parts of the OS periodically. If you only had one floppy drive, you'd have to continuously eject and insert the OS disk and your data disk when running some commands. It was far more desirable to have two drives available, so the OS disk could be left in one drive for most of the time.



    Having two floppy drives also speeds up copying files between different disks, but this is a secondary benefit.



    The provision of two floppy drives was also common with other machines, such as the IBM PC and the BBC Micro (though the latter had its OS in a ROM on the motherboard). When hard drives were installed in computers, the OS could be installed there, and there was no longer such a benefit from having a second floppy drive.






    share|improve this answer





















    • Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
      – supercat
      12 hours ago










    • @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
      – alephzero
      11 hours ago












    • @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
      – supercat
      11 hours ago

















    up vote
    1
    down vote













    The Osborne 1, like many computers of the time, had no means of data storage other than floppy disks. On powering up, the user would be prompted to insert the operating system disk, so the machine could boot.



    Even when running other software, the computer would need to access and run parts of the OS periodically. If you only had one floppy drive, you'd have to continuously eject and insert the OS disk and your data disk when running some commands. It was far more desirable to have two drives available, so the OS disk could be left in one drive for most of the time.



    Having two floppy drives also speeds up copying files between different disks, but this is a secondary benefit.



    The provision of two floppy drives was also common with other machines, such as the IBM PC and the BBC Micro (though the latter had its OS in a ROM on the motherboard). When hard drives were installed in computers, the OS could be installed there, and there was no longer such a benefit from having a second floppy drive.






    share|improve this answer





















    • Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
      – supercat
      12 hours ago










    • @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
      – alephzero
      11 hours ago












    • @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
      – supercat
      11 hours ago















    up vote
    1
    down vote










    up vote
    1
    down vote









    The Osborne 1, like many computers of the time, had no means of data storage other than floppy disks. On powering up, the user would be prompted to insert the operating system disk, so the machine could boot.



    Even when running other software, the computer would need to access and run parts of the OS periodically. If you only had one floppy drive, you'd have to continuously eject and insert the OS disk and your data disk when running some commands. It was far more desirable to have two drives available, so the OS disk could be left in one drive for most of the time.



    Having two floppy drives also speeds up copying files between different disks, but this is a secondary benefit.



    The provision of two floppy drives was also common with other machines, such as the IBM PC and the BBC Micro (though the latter had its OS in a ROM on the motherboard). When hard drives were installed in computers, the OS could be installed there, and there was no longer such a benefit from having a second floppy drive.






    share|improve this answer












    The Osborne 1, like many computers of the time, had no means of data storage other than floppy disks. On powering up, the user would be prompted to insert the operating system disk, so the machine could boot.



    Even when running other software, the computer would need to access and run parts of the OS periodically. If you only had one floppy drive, you'd have to continuously eject and insert the OS disk and your data disk when running some commands. It was far more desirable to have two drives available, so the OS disk could be left in one drive for most of the time.



    Having two floppy drives also speeds up copying files between different disks, but this is a secondary benefit.



    The provision of two floppy drives was also common with other machines, such as the IBM PC and the BBC Micro (though the latter had its OS in a ROM on the motherboard). When hard drives were installed in computers, the OS could be installed there, and there was no longer such a benefit from having a second floppy drive.







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered 12 hours ago









    Kaz

    1564




    1564












    • Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
      – supercat
      12 hours ago










    • @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
      – alephzero
      11 hours ago












    • @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
      – supercat
      11 hours ago




















    • Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
      – supercat
      12 hours ago










    • @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
      – alephzero
      11 hours ago












    • @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
      – supercat
      11 hours ago


















    Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
    – supercat
    12 hours ago




    Why would a machine of that error need to access the OS while running a program? Reloading the command-prompt handler after exiting would be commonplace, but if part of the OS got displaced by another program, it wouldn't be able to reload until that program gave up the memory, which wouldn't usually happen until that program exited.
    – supercat
    12 hours ago












    @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
    – alephzero
    11 hours ago






    @supercat Just as now, an "OS" like CP/M included a collection of stand-alone utility programs as well as the permanently resident code. If you wanted to use CPM's "PIP" to copy a file from one disk to another on a single-drive system, you would have to (1) insert the CPM disk to start PIP (2) insert the first data disk to read a chunk of data into memory (3) insert the second data disk to write the data (4) repeat steps 2 and 3 till done. The probability of "user error" was not small! With two drives, you only needed to do one disk change. to swap the OS disk for one of the data disks.
    – alephzero
    11 hours ago














    @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
    – supercat
    11 hours ago






    @alephzero: When copying data from one disk to another, having two drives was better than one, obviously. My issue was with the first sentence of the second paragraph. If a program wanted to use PIP to copy a file, it would need to save its state and arrange things so that when PIP exited, the disk in the first drive would contain a file with a certain special name whose last block contained a command to re-run the original program and have it reload its state. Were there any programs that went through that rigmarole to use PIP rather than simply using their own internal copy-file code?
    – supercat
    11 hours ago












    up vote
    0
    down vote













    Since the computer only has disk drives and no hard-disk, the normal usage was to have the system programs and a word processor or database handler on one diskette and using the other for data or documents.
    Those drives were single side, single density as standard, which gave a storage capacity of somewhere around 100 kBytes each.






    share|improve this answer

























      up vote
      0
      down vote













      Since the computer only has disk drives and no hard-disk, the normal usage was to have the system programs and a word processor or database handler on one diskette and using the other for data or documents.
      Those drives were single side, single density as standard, which gave a storage capacity of somewhere around 100 kBytes each.






      share|improve this answer























        up vote
        0
        down vote










        up vote
        0
        down vote









        Since the computer only has disk drives and no hard-disk, the normal usage was to have the system programs and a word processor or database handler on one diskette and using the other for data or documents.
        Those drives were single side, single density as standard, which gave a storage capacity of somewhere around 100 kBytes each.






        share|improve this answer












        Since the computer only has disk drives and no hard-disk, the normal usage was to have the system programs and a word processor or database handler on one diskette and using the other for data or documents.
        Those drives were single side, single density as standard, which gave a storage capacity of somewhere around 100 kBytes each.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 12 hours ago









        UncleBod

        566110




        566110






















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