What is claimed is:
1. A method for controlling storage of data on a removable external recording medium which can be installed on a storage system, comprising the steps of:
halting of data storage on said external recording medium when judgment is made not to store data on said external recording medium and, beginning storage of data which follows data stored on said external recording medium in an internal storage means.
2. A method for controlling storage of data according to claim 1, comprising the steps of:
comparing an amount of free space on said external recording medium with an amount of data to be stored next;
storing data on said external recording medium if the amount of free space is larger than the amount of data; and
storing data in said internal storage means if the amount of free space is insufficient.
3. A method for controlling storage of data according to claim 1, comprising the steps of:
judging whether capacity of said external recording medium is sufficient for data to be stored next;
storing data on said external recording medium if the capacity of said external recording medium is sufficient; and
storing data in said internal storage means if the capacity of said external recording medium is not sufficient.
4. A method for controlling storage of data according to claim 1, wherein data in said internal storage means is updated by sequentially-entered data and wherein, when the amount of data stored on said external recording medium has reached a predetermined amount, data which follows data stored on said external recording medium is held in said internal storage means.
5. A method for controlling storage of data according to claim 1, wherein, when said external recording medium is exchanged from a first external recording medium to a second external recording medium, data held in said internal storage means is stored on said second external recording medium.
6. A method for controlling storage of data according to claim 5, wherein, on said second external recording medium, data stored in said internal storage means is stored first and then data entered after said second external recording medium is installed is stored.
7. A method for controlling storage of data according to claim 5, wherein data entered after said second external recording medium is installed is stored first on said second external recording medium and wherein data held in said internal storage means is stored on said second external recording medium when data supply after said medium installation is stopped.
8. A method for controlling storage of data on a removable external recording medium which can be installed on a storage system wherein, when said external recording medium is removed, data which follows data stored on said external recording medium is held in an internal storage means.
9. A method for controlling storage of data according to claim 8 wherein, when a second external recording medium is installed, data which is held in said internal storage means and which is entered after a first external recording medium is removed is stored in said second external recording medium.
10. A method for controlling storage of data according to claim 9, wherein, on said second external recording medium, data stored in said internal storage means is stored before data entered after said second external recording medium is installed is stored.
11. A method for controlling storage of data according to claim 9, wherein data entered after said second external recording medium is installed is stored first on said second external recording medium and wherein data held in said internal storage means is stored on said second external recording medium when data supply after medium installation is stopped.
12. A data storage control system comprising:
an external storage controller which stores data on a removable external recording medium which can be installed on a storage system;
an internal storage controller which stores data in internal storage means on an auxiliary basis; and
a main controller which controls said external storage controller and said internal storage controller, said main controller is stopping writing data on said external recording medium and holding data, which follows data stored on said external recording medium, in said internal storage means when judgment is made not to store data on said external recording medium.
13. A data storage system comprising:
an encoder for coding entered data into variable length data;
an external storage controller which stores data on a removable external recording medium which can be installed on said storage system;
an internal storage controller which stores data in internal storage means on an auxiliary basis; and
a main controller which controls said external storage controller and said internal storage controller, said main controller is stopping writing data on said external recording medium and holding data, which follows data stored on said external recording medium, in said internal storage means when judgment is made not to store data on said external recording medium.
14. A data storage system according to claim 13, wherein said main controller has a comparator which compares an amount of free space on said external recording medium with an amount of data to be stored next;
wherein said main controller stores data on said external recording medium if the amount of free space is larger than the amount of data; and
wherein said main controller stores data in said internal storage means if the mount of free space is insufficient.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A torsional vibration measuring instrument comprising:
a plurality of reflecting means arranged with stipulated intervals therebetween along surface of a rotator of which torsional vibration is to be measured;
a pulse light irradiating means for irradiating a repetitive pulse light beam to the plurality of reflecting means;
an outgoing-transmitting means for transmitting the irradiated pulse light beam;
a plurality of transmitting-receiving means for irradiating the transmitted pulse light beam to the plurality of reflecting means, and for receiving plurality of reflected pulse light beams which have been reflected by the plurality of reflecting means;
an incoming-transmitting means for transmitting the plurality of reflected pulse light beams which have been received;
a plurality of detecting means for detecting the plurality of reflected pulse light beams which have been transmitted by the incoming-transmitting means; and
a signal processing means for processing a plurality of pulse output signals which have been outputted from the plurality of detecting means and for calculating torsional vibration frequency of the rotator to be measured.
2. The torsional vibration measuring instrument of claim 1 characterized that the pulse light beam irradiating means can irradiate pulse light beam with variable pulse repetitive frequency and with variable pulse time width.
3. The torsional vibration measuring instrument of claim 1 characterized that the pulse light beam irradiating means includes a plurality of separated units each corresponding to one of the plurality of transmitting-receiving means.
4. The torsional vibration measuring instrument of claim 1 characterized that the ongoing-transmitting means includes a beam splitter for splitting the pulse light irradiated from the pulse light irradiating means and for transmitting the pulse light.
5. The torsional vibration measuring instrument of claim 1 characterized that the plurality of reflecting means and the plurality of transmitting-receiving means are aligned in radial direction of the rotator to be measured, and that the pulse light beams are directed so that the pulse light beam is irradiated substantially perpendicular to the plurality of reflector means.
6. The torsional vibration measuring instrument of claim 1 characterized that the outgoing-transmission means and the incoming transmission means have at least one light dividing means, and that the outgoing-transmission means and the incoming transmission means utilize at least partly a common light guide.
7. The torsional vibration measuring instrument of claim 1 characterized that the signal processing means calculate torsional vibration frequency of the rotator based upon difference of rotational periods obtained by the corresponding pulse output signals.
8. The torsional vibration measuring instrument of claim 1 characterized that the transmitting-receiving means are arranged in peripheral direction of the rotator to be measured.
9. The torsional vibration measuring instrument of claim 1 characterized that at least three transmitting-receiving means and at least three reflecting means are arranged along axial direction of the rotator.
10. The torsional vibration measuring instrument of claim 1 characterized that the reflecting means has a high reflection region where the light beam is reflected with a high reflection coefficient, and a low reflection region where the light beam is reflected with a reflection coefficient lower than the high reflection coefficient, and that the high reflection region and the low reflection region are distributed along peripheral direction of the rotator to be measured.
11. The torsional vibration measuring instrument of claim 1 characterized that the plurality of reflecting means each includes a plurality of units of reflecting means attached on the rotator to be measured.
12. The torsional vibration measuring instrument of claim 1 characterized that the signal processing means calculates the torsional vibration frequency of the rotator to be measured, by differentiating the plurality of pulse output signals which are outputted from the plurality of detecting means.
13. The torsional vibration measuring instrument of claim 1 characterized that the signal processing means calculates the torsional vibration frequency of the rotator to be measured, by digital counting of the plurality of pulse output signal which are outputted from the plurality of detecting means.
14. The torsional vibration measuring instrument of claim 1 characterized that the signal processing means calculates the torsional vibration frequency of the rotator to be measured, using lengths of the plurality of reflecting means in peripheral direction.
15. The torsional vibration measuring instrument of claim 1 characterized that wavelength of pulse light of the pulse irradiating means can be changed.
16. The torsional vibration measuring instrument of claim 1 characterized that the detecting means include wavelength selecting means for selecting the reflected pulse light beam using the wavelength and for detecting the selected pulse light beam.
17. The torsional vibration measuring instrument of claim 1 characterized that size of the pulse light beam which is irradiated to the reflecting means is much smaller than lengths of the reflecting means in axial and peripheral directions of the rotator to be measured.