Disk Activity Monitor for multiple disks

[Ellis Dee]

I'm adding a second hard drive -- woohoo! -- and was wondering how to update my hard drive activity monitor to differentiate activity between the two physical drives.

Looking at the code I use for the activity monitor (which I've been using and loving for almost a decade now) I'm not seeing any reference to a particular drive anywhere.

clsHDMon.cls:

' // Written by Ellis Dee //
' Thanks to Matt Pietrek of MSJ and Edgemeal of vbforums.com
Option Explicit
 
Public Event Activity()
Public Event Idle()
 
Private Const ReadColor = 16761024 ' ?RGB(192, 192, 255)
Private Const WriteColor = 16744576 ' ?RGB(128, 128, 255)
Private Const InactiveColor = 6316128  ' ?RGB(96, 96, 96)
Private Const BorderColor = 0 ' ?RGB(0, 0, 0)
 
Private mlngRead As Long
Private mlngWrite As Long
Private mlngIdle As Long
Private mblnIndicator As Boolean
 
Private mblnValid As Boolean
Private mlngQuery As Long
Private mlngReadCounter As Long
Private mlngWriteCounter As Long
 
Private Const ERROR_SUCCESS = 0
 
Private Enum PDH_STATUS
    PDH_CSTATUS_VALID_DATA = &H0
    PDH_CSTATUS_NEW_DATA = &H1
    PDH_CSTATUS_NO_MACHINE = &H800007D0
    PDH_CSTATUS_NO_INSTANCE = &H800007D1
    PDH_MORE_DATA = &H800007D2
    PDH_CSTATUS_ITEM_NOT_VALIDATED = &H800007D3
    PDH_RETRY = &H800007D4
    PDH_NO_DATA = &H800007D5
    PDH_CALC_NEGATIVE_DENOMINATOR = &H800007D6
    PDH_CALC_NEGATIVE_TIMEBASE = &H800007D7
    PDH_CALC_NEGATIVE_VALUE = &H800007D8
    PDH_DIALOG_CANCELLED = &H800007D9
    PDH_CSTATUS_NO_OBJECT = &HC0000BB8
    PDH_CSTATUS_NO_COUNTER = &HC0000BB9
    PDH_CSTATUS_INVALID_DATA = &HC0000BBA
    PDH_MEMORY_ALLOCATION_FAILURE = &HC0000BBB
    PDH_INVALID_HANDLE = &HC0000BBC
    PDH_INVALID_ARGUMENT = &HC0000BBD
    PDH_FUNCTION_NOT_FOUND = &HC0000BBE
    PDH_CSTATUS_NO_COUNTERNAME = &HC0000BBF
    PDH_CSTATUS_BAD_COUNTERNAME = &HC0000BC0
    PDH_INVALID_BUFFER = &HC0000BC1
    PDH_INSUFFICIENT_BUFFER = &HC0000BC2
    PDH_CANNOT_CONNECT_MACHINE = &HC0000BC3
    PDH_INVALID_PATH = &HC0000BC4
    PDH_INVALID_INSTANCE = &HC0000BC5
    PDH_INVALID_DATA = &HC0000BC6
    PDH_NO_DIALOG_DATA = &HC0000BC7
    PDH_CANNOT_READ_NAME_STRINGS = &HC0000BC8
End Enum
 
Private Declare Function PdhVbGetOneCounterPath Lib "PDH.DLL" (ByVal PathString As String, ByVal PathLength As Long, ByVal DetailLevel As Long, ByVal CaptionString As String) As Long
Private Declare Function PdhVbCreateCounterPathList Lib "PDH.DLL" (ByVal PERF_DETAIL As Long, ByVal CaptionString As String) As Long
Private Declare Function PdhVbGetCounterPathFromList Lib "PDH.DLL" (ByVal Index As Long, ByVal Buffer As String, ByVal BufferLength As Long) As Long
Private Declare Function PdhOpenQuery Lib "PDH.DLL" (ByVal Reserved As Long, ByVal dwUserData As Long, ByRef mlngQuery As Long) As PDH_STATUS
Private Declare Function PdhCloseQuery Lib "PDH.DLL" (ByVal mlngQuery As Long) As PDH_STATUS
Private Declare Function PdhVbAddCounter Lib "PDH.DLL" (ByVal QueryHandle As Long, ByVal CounterPath As String, ByRef CounterHandle As Long) As PDH_STATUS
Private Declare Function PdhCollectQueryData Lib "PDH.DLL" (ByVal QueryHandle As Long) As PDH_STATUS
Private Declare Function PdhVbIsGoodStatus Lib "PDH.DLL" (ByVal StatusValue As Long) As Long
Private Declare Function PdhVbGetDoubleCounterValue Lib "PDH.DLL" (ByVal CounterHandle As Long, ByRef CounterStatus As Long) As Double
 
Public Sub GetActivity(plngRead As Long, plngWrite As Long)
    If mblnValid Then
        PdhCollectQueryData (mlngQuery)
        plngRead = GetCounter(mlngReadCounter) ' PhysicalDisk Total % Disk Read Time
        plngWrite = GetCounter(mlngWriteCounter) ' PhysicalDisk Total % Disk Write Time
    End If
End Sub
 
Private Function GetCounter(plngCounter As Long) As Long
    Dim enStatus As PDH_STATUS
    Dim dblActivity As Double
    
    dblActivity = PdhVbGetDoubleCounterValue(plngCounter, enStatus)
    ' Verify that when we queried, the returned value was valid
    If Not ((enStatus = PDH_CSTATUS_VALID_DATA) Or (enStatus = PDH_CSTATUS_NEW_DATA)) Then dblActivity = 0
    Select Case dblActivity
        Case Is < 10: GetCounter = 0
        Case Is > 100: GetCounter = 5
        Case Else: GetCounter = 1 + (Round(dblActivity) - 1) \ 20
    End Select
End Function
 
Private Sub Class_Initialize()
    StartMonitor
End Sub
 
Private Sub Class_Terminate()
    StopMonitor
End Sub
 
Public Sub StopMonitor()
    If mlngQuery Then PdhCloseQuery (mlngQuery) ' Free the PDH query
    mblnValid = False
End Sub
 
Public Sub StartMonitor()
    Dim enStatus As PDH_STATUS
    
    enStatus = PdhOpenQuery(0, 1, mlngQuery)
    If enStatus <> ERROR_SUCCESS Then Exit Sub
    mblnValid = True
    PdhVbAddCounter mlngQuery, "\PhysicalDisk(_Total)\% Disk Read Time", mlngReadCounter
    PdhVbAddCounter mlngQuery, "\PhysicalDisk(_Total)\% Disk Write Time", mlngWriteCounter
End Sub
 
Public Sub Timer(ppic As PictureBox)
    Dim lngNewRead As Long
    Dim lngNewWrite As Long
    Dim blnRedraw As Boolean
    Dim blnOldIndicator As Boolean
    
    If Not mblnValid Then Exit Sub
    blnOldIndicator = mblnIndicator
    Me.GetActivity lngNewRead, lngNewWrite
    If lngNewRead = 0 And lngNewWrite = 0 Then
        mlngIdle = mlngIdle + 1
        mblnIndicator = (mlngIdle < 15)
    Else
        mblnIndicator = True
        mlngIdle = 0
    End If
    If lngNewRead <> mlngRead Then
        mlngRead = lngNewRead
        blnRedraw = True
    End If
    If lngNewWrite <> mlngWrite Then
        mlngWrite = lngNewWrite
        blnRedraw = True
    End If
    If mblnIndicator Then
        If blnRedraw Then
            ppic.Line (0, 0)-(31, 31), BorderColor, BF
            DrawIndicator ppic, mlngRead, ReadColor, 2
            DrawIndicator ppic, mlngWrite, WriteColor, 17
            RaiseEvent Activity
        End If
    ElseIf blnOldIndicator Then
        RaiseEvent Idle
    End If
End Sub
 
Private Sub DrawIndicator(ppic As PictureBox, plngActivity As Long, plngColor As Long, plngLeft As Long)
    Dim lngRight As Long
    Dim lngColor As Long
    Dim lngY As Long
    Dim i As Long
    
    lngRight = plngLeft + 12
    For i = 0 To 4
        If i < plngActivity Then lngColor = plngColor Else lngColor = InactiveColor
        lngY = 26 - i * 6
        ppic.Line (plngLeft, lngY)-(lngRight, lngY + 3), lngColor, BF
    Next
End Sub

My indicator light is just a simple userdrawn picturebox, and right now looks like this in practice, with reads on the left and writes on the right:



Conceptually, I'm not quite sure yet how I want to show two drive indicators in the same icon, but first I need to figure out if I can even set up independent monitors for both physical drives.

EDIT: After around 3-4 seconds of inactivity, it reverts to a static icon:



This program does more than just monitor hard drive activity. It's my place to put any utilities I write and want easy access to, like for instance my backup routine that I'm absolutely loving. The indicator is merely the justification for it taking up icon space in the tray.

[dz32]

[...]

[fafalone]

I use an app that uses that string format for perfmon meters... selecting an individual disk looks like \PhysicalDisk(3 G:)\% Disk Read Time

where the first drive is (0 E:), which is odd since it's not the primary disk, C:\, which has the OS and is on SATA 0.

[Ellis Dee]

Cool, that's at least a place to start. Thanks much.

I'll post back here with follow-up questions and/or results once I get my second drive installed.

For the class itself, I'm thinking enumerate the hard drives on class_init and then branch off to either this existing code for single-drive systems or a new branch for two-drive systems. I won't be able to test single-drive systems any longer, sadly, but not a huge deal. This code has worked well for all my computers since writing it: XP, 7 and 10.

[Ellis Dee]

In the meantime, anyone have any ideas/suggestions for how to show activity on two drives in a single icon?

The most obvious is splitting the indicator vertically, so the left side (currently light blue reads) would be two narrow columns showing reads and writes for the system drive and the right side (currently dark blue writes) would be two narrow columns for the data drive. Probably different colors; maybe greens for the data drives?

Another option would be four square quadrants, with the tops being reads and the bottoms writes, left system right data. Activity levels could be represented by either making the squares bigger/smaller, or maybe using color gradients: darker = less activity, brighter = more activity.

Another possibly ugly option might be to leave the primary indicator exactly as-is, but add the secondary indicator to the negative space. (The dark "background" lines between indicator lines.) This option would live or die based on colors chosen, I think.

Any other ideas?

EDIT: Another option could be to leave the read and write columns alone (I kind of like their dimensions, having gotten very used to it over the past decade) and use colors to denote what's going on:

Blues = system drive only
Greens = data drive only
Purples = both drives

Or whatever colors end up working. The idea here would be to combine both drives into one bar. So, just throwing out examples, if the system drive is being read at 40% (two bars) and the data drive is being read at 80% (four bars) the read indicator's five lines, from top to bottom, would be:

5 (<=100%): Dark Gray (background color)
4 (<=80%): Green
3 (<=60%): Green
2 (<=40%): Purple
1 (<=20%): Purple

This again would live and die based on colors chosen.

[fafalone]

Splitting vertically seems to me the most intuitive option.. keep the colors and two bars that exist now, and vertically split each bar with reads in one column and writes in the other. Any more than two drives just won't look good at that icon size though.

[Ellis Dee]

Splitting vertically seems to me the most intuitive option.. keep the colors and two bars that exist now, and vertically split each bar with reads in one column and writes in the other. Any more than two drives just won't look good at that icon size though.

This was my first choice, but after throwing together some mockups I don't think there's enough width on split columns to be readily seen at a glance.

Here's a mockup of the split columns, blue and green:


Here's a mockup of the four quadrants, with larger dots denoting more activity:


Here's a mockup of four quadrants always filled, with brightness indicating activity:


Here's a mockup of using a third color to depict activity on both drives:


Not really loving any of these so far, but of course I haven't tweaked any of the colors to really work. (These were quickly thrown together.)

Another possibility is a hybrid of the three-colors option. Something like use blue if activity is mostly system, green if mostly data, or yellow if roughly equal on both. So like 60% system 20% data would be considered mostly system and show as blue, while 40% on both would show as combined yellow. All bars would stick to a single color scheme regardless of value.

This is the most pleasing for static screenshots, but could become a flickering nightmare in practice.

[Ellis Dee]

Actually, now that I'm running my backup in preparation for adding the second hard drive I'm noticing that my disk monitor is showing writes to the flash drive. And I kind of like it. Given that, I think I might just stick with the global "any activity" unified indicator.



Man this Ultra is slooooooow. hehheh.

[fafalone]

Yeah 'Physical Disk' will include flash drives, or any mass storage on USB, but not network drives even if mapped to a letter. If a physical disk has multiple partitions, it would still be seen as a single disk ('LogicalDisk' will show all the partitions as different drives, but again no network mapped drives).