1. A hard disk drive, comprising:
a disk that has at least one track, said track having at least one servo sector that has an A servo bit and a B servo bit;
a head coupled to said disk;
an actuator arm coupled to said head;
a voice coil motor actuator coupled to said actuator arm; and,
a controller that determines a position error signal gain based on a product of a total servo loop gain and a function defined by a slope of a line formed by a difference between said A and B servo bits measured at N off-track positions.
2. The hard disk drive of claim 1, wherein said off-track positions are up to one-quarter of a track.
3. The hard disk drive of claim 1, wherein said position error signal gain is a function of a plant gain defined by the equation:
K
plant
=
X
\u2211
n
=
1
N
\u2062
\u0394
\u2062
\u2062
u
\u0394
\u2062
\u2062
y
AB
,
n
\u2062
(
y
AB
,
n
+
1
–
y
AB
,
n
)
where;
X=the outer limit of said N off-track positions;
\u0394
\u2062
\u2062
u
\u0394
\u2062
\u2062
y
AB
,
n
=
the
\u2062
\u2062
slope
\u2062
\u2062
of
\u2062
\u2062
said
\u2062
\u2062
function
;
y
AB
,
n
+
1
=
the
\u2062
\u2062
difference
\u2062
\u2062
between
\u2062
\u2062
the
\u2062
\u2062
A
\u2062
\u2062
and
\u2062
\u2062
B
\u2062
\u2062
servo
burst
\u2062
\u2062
at
\u2062
\u2062
each
\u2062
\u2062
said
\u2062
\u2062
N
\u2062
\u2062
off
\u2062
–
\u2062
track
\u2062
\u2062
position
.
4. The hard disk drive of claim 1, wherein said total servo loop gain is measured at said N off-track positions.
5. The hard disk drive of claim 1, wherein said controller centers said head on said track of said disk utilizing said position error signal gain.
6. A method for determining a position error signal gain used in a hard disk drive, comprising:
determining a total servo loop gain;
determining a function defined by a slope of a line formed by a difference between A and B servo bits measured at N off-track positions; and,
determining a position error signal gain from a product of the total servo loop gain and the function.
7. The method of claim 6, wherein the off-track positions are up to one-quarter of a track.
8. The method of claim 6, wherein the position error signal gain is a function of a plant gain defined by the equation:
K
plant
=
X
\u2211
n
=
1
N
\u2062
\u0394
\u2062
\u2062
u
\u0394
\u2062
\u2062
y
AB
,
n
\u2062
(
y
AB
,
n
+
1
–
y
AB
,
n
)
where;
X=the outer limit of said N off-track positions;
\u0394
\u2062
\u2062
u
\u0394
\u2062
\u2062
y
AB
,
n
=
the
\u2062
\u2062
slope
\u2062
\u2062
of
\u2062
\u2062
said
\u2062
\u2062
function
;
y
AB
,
n
+
1
=
the
\u2062
\u2062
difference
\u2062
\u2062
between
\u2062
\u2062
the
\u2062
\u2062
A
\u2062
\u2062
and
\u2062
\u2062
B
\u2062
\u2062
servo
burst
\u2062
\u2062
at
\u2062
\u2062
each
\u2062
\u2062
said
\u2062
\u2062
N
\u2062
\u2062
off
\u2062
–
\u2062
track
\u2062
\u2062
position
.
9. The method of claim 6, wherein the total servo loop gain is measured at the N off-track positions.
10. The method of claim 6, further comprising centering a head on a disk track utilizing the position error signal gain.
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. An information sharing device comprising:
an information providing unit providing electronic information in a state that allows the electronic information to have annotation information attached;
an annotation storing unit storing annotation information to be attached to the electronic information;
an attribute storing unit storing attribute information which indicates a disclosure range of the annotation information; and
an annotation management unit, when requested from a user to provide annotation information, retrieving annotation information that is disclosed to the user from the annotation storing unit by consulting the attribute storing unit to provide the annotation information to a terminal of the user.
2. An information sharing device according to claim 1, wherein the attribute storing unit stores as the attribute information the level of importance of annotation information and e-mail addresses of the respective users, and has a notification unit sending, when annotation information whose level of importance is stated to be equal to or higher than a predetermined level by its attribute information is stored in the annotation storing unit, e-mail to users who are within the disclosure range of the annotation information.
3. An information sharing device according to claim 1, wherein the attribute storing unit stores as the attribute information user identification information of a user who has created annotation information and e-mail addresses of the respective users, and has a notification unit retrieving, when annotation information that follows up the former annotation information is added, the e-mail address of the user who has created the original annotation information by consulting the attribute storing unit to send, via e-mail, the URL where the follow-up annotation information is displayed or the follow-up annotation information itself to the user at the retrieved address.
4. An information sharing device according to claim 2, wherein the notification unit extracts, at predetermined intervals, from annotation information available to the respective users, summary information of annotation information about which no e-mail has been sent, and sends the summary information via e-mail to the address of a corresponding user.
5. An information sharing device according to claim 2, comprising a mail registration unit which, when the notification unit sends the e-mail including identification information of the annotation information and e-mail containing the identification information and follow-up information for the annotation information is returned, extracts the follow-up information from the returned e-mail to store the follow-up information in the annotation storing unit as follow-up annotation information for annotation information that is specified by the identification information.
6. An information sharing device according to claim 5, wherein when the returned e-mail has a multimedia file attached thereto, the mail registration unit registers the multimedia file in a media management unit and adds information on a link to the multimedia file to the follow-up annotation information.
7. An information sharing device according to claim 1, wherein when notified from the user terminal to create follow-up annotation data, the annotation management unit changes the color or luminance of the text or image which is the original annotation information, and provides the data as quotation data to the user terminal.
8. An information sharing device according to claim 1, wherein when a request to provide annotation information is received from a terminal of a first user along with identification information that specifies a second user, the annotation management unit extracts, from the annotation storing unit, annotation information which is available to the first user and which is created by the second user who matches the identification information to provide the annotation information to the terminal of the first user.
9. An information sharing device according to claim 1, comprising an annotation analyzing unit which, when an instruction to compile annotation information for the electronic information is sent from one of the user terminals, compiles annotation information added to the electronic information for every predetermined number of blocks and presents the compiling result to the user terminal.
10. An information sharing device according to claim 1, comprising an annotation searching unit which looks up the annotation information and electronic information to which the annotation information is added for a search keyword to retrieve annotation information containing the search keyword and annotation information added to information that contains the search keyword.
11. An information sharing device according to claim 1, comprising an annotation analyzing unit which calculates the similarity between annotation information or between groups of annotation information and which outputs data for displaying annotation information in tree format or as a two-dimensional distribution based on the similarity obtained.
12. An information sharing device according to claim 1, comprising an understanding degree judging unit which estimates user’s degree of understanding of a document based on annotation data added to electronic information from the terminal of the user.
13. An online learning system comprising an information sharing device, terminals of students as the users and to terminals of teachers as the users, the information sharing device including:
an information providing unit providing electronic information to the terminals of students as the users and to terminals of teachers as the users;
an annotation storing unit storing annotation information to be attached to the electronic information;
an attribute storing unit storing attribute information which indicates a disclosure range of the annotation information; and
an annotation management unit, when requested from a user to provide annotation information, retrieving annotation information that is disclosed to the user from the annotation storing unit by consulting the attribute storing unit to provide the annotation information to a terminal of the user.
14. An information sharing method comprising causing a computer to execute the steps of:
providing electronic information in a state that allows the electronic information to have annotation information attached;
storing annotation information to be attached to the electronic information in an annotation storing unit;
storing attribute information which indicates a disclosure range of the annotation information in an attribute storing unit; and
retrieving, when requested from a user to provide annotation information, annotation information that is disclosed to the user from the annotation storing unit by consulting the attribute storing unit to provide the annotation information to a terminal of the user.
15. An information sharing method according to claim 14, wherein the step of storing annotation information includes the steps of storing the level of importance of annotation information and e-mail addresses of the respective users as attribute information in the attribute storing unit, and sending e-mail to users within the disclosure range when annotation information whose level of importance is stated to be equal to or higher than a predetermined level by its attribute information is stored in the annotation storing unit.
16. An information sharing method according to claim 14, wherein the step of storing annotation information includes:
storing identification information of a user who has created annotation information and e-mail addresses of the respective users as the attribute information in the attribute storing unit; and
retrieving, when annotation information that follows up the former annotation information is added, the e-mail address of the user that has created the original annotation information by consulting the attribute storing unit to send, via e-mail, the URL where the follow-up annotation information is displayed or the follow-up annotation information itself to the user at the retrieved address.
17. An information sharing method according to claim 15, comprising the steps of extracting, at predetermined intervals, from annotation information available to the respective users, summary information of annotation information about which no e-mail has been sent, and sending the summary information via e-mail to the address of a corresponding user.
18. An information sharing method according to claim 15, comprising providing a mail registration unit which, when the e-mail sent in the step of sending e-mail contains identification information of the annotation information and e-mail containing follow-up information for the annotation information and the identification information is returned, extracts the follow-up information from the returned e-mail and stores the follow-up information in the annotation storing unit as follow-up annotation information for annotation information that is specified by the identification information.
19. An information sharing method according to claim 18, wherein the computer has a media management unit storing a multimedia file and, when the returned e-mail has a multimedia file attached thereto, the multimedia file is registered in the media management unit and information on a link to the multimedia file is added to the follow-up annotation information in the step of registering annotation information.
20. An information sharing method according to claim 14, comprising the steps of changing, upon receiving a notification to create follow-up annotation data from the user terminal, the color or luminance of the text or image which is the original annotation information, and providing the data as quotation data to the user terminal.
21. An information sharing method according to claim 14, wherein when a request to provide annotation information is received from a terminal of a first user along with identification information that specifies a second user, annotation information which is available to the first user and which is created by the second user who matches the identification information is extracted from the annotation storing unit to provide the annotation information to the terminal of the first user.
22. An information sharing method according to claim 14, comprising the steps of compiling, when an instruction to compile annotation information for the electronic information is sent from one of the user terminals, annotation information added to the electronic information for every predetermined number of blocks to provide the compiling result to the user terminal.
23. An information sharing method according to claim 14, comprising the step of looking up the annotation information and electronic information to which the annotation information is added for a search keyword to retrieve annotation information containing the search keyword and annotation information added to information that contains the search keyword.
24. An information sharing method according to claim 14, comprising the steps of calculating the similarity between annotation information or between groups of annotation information and outputting data for displaying annotation information in tree format or as a two-dimensional distribution based on the similarity obtained.
25. An information sharing method according to claim 14, comprising the step of estimating user’s degree of understanding of a document based on annotation data added to the electronic information from the terminal of the user.
26. A storage medium which stores an information sharing program for causing a computer to execute the steps of:
providing electronic information in a state that allows the electronic information to have annotation information attached;
storing annotation information to be attached to the electronic information in an annotation storing unit;
storing attribute information which indicates a disclosure range of the annotation information in an attribute storing unit; and
retrieving, when requested from a user to provide annotation information, annotation information that is disclosed to the user from the annotation storing unit by consulting the attribute storing unit to provide the annotation information to a terminal of the user.
27. An information sharing system comprising user terminals, and an information sharing device for providing the user terminals with electronic information,
the information sharing device including:
an information providing unit providing electronic information in a state that allows the electronic information to have annotation information attached;
an annotation storing unit storing annotation information to be attached to the electronic information;
an attribute storing unit storing attribute information which indicates a disclosure range of the annotation information; and
an annotation management unit, when requested from a user to provide annotation information, retrieving annotation information that is disclosed to the user from the annotation storing unit by consulting the attribute storing unit to provide the annotation information to a terminal of the user,
the user terminals each having:
an information requesting unit requesting the information sharing device to provide electronic information and annotation information; and
display means for displaying electronic information obtained from the information sharing device with annotation information superimposed on the electronic information.
28. A user terminal connected to an information sharing device via a network, comprising:
an information requesting unit requesting the information sharing device to provide the electronic information and annotation information, wherein the information sharing device includes an information providing unit providing electronic information in a state that allows the electronic information to have annotation information attached, an annotation storing unit storing annotation information to be attached to the electronic information, an attribute storing unit storing attribute information which indicates a disclosure range of the annotation information, and an annotation management unit, when requested from a user to provide annotation information, retrieving annotation information that is disclosed to the user from the annotation storing unit by consulting the attribute storing unit to provide the annotation information to a terminal of the user; and
display means for displaying electronic information obtained from the information sharing device with annotation information superimposed on the electronic information.
29. A user terminal according to claim 28, comprising:
an annotation creating unit creating annotation information that contains at least information about the contents of an annotation, the location where the annotation is to be attached, and the range of disclosure of the annotation for the electronic information or annotation information; and
an annotation transmitting unit sending the created annotation information to the information sharing device.
30. A user terminal according to claim 28, comprising:
an annotation creating unit changing, when follow-up annotation information is to be added to the annotation information, the color or luminance of the text or image which is the original annotation information to obtain quotation information, and then creating annotation information by adding the follow-up contents to the quotation data; and
an annotation transmitting unit sending the created annotation information to the information sharing device.
31. An information sharing program for user terminals which is run in user terminals connected to the information sharing device according to claim 1 via a network, for causing the user terminals to execute the steps of:
requesting the information sharing device to provide the electronic information and annotation information; and
displaying electronic information obtained from the information sharing device with annotation information superimposed on the electronic information.