Single connection for multiple Get-WmiObject calls

Question

The script below successfully obtains the manufacturer, model, serial number, and operating system from each computer I provide in hostnames.txt. However, it is slow because it must connect to WMI on each computer three times.

$OS = Get-WmiObject Win32_OperatingSystem -ComputerName $Computer
$CS = Get-WmiObject Win32_ComputerSystem -ComputerName $Computer
$BIOS = Get-WmiObject Win32_Bios -ComputerName $Computer

Using PowerShell, how can I connect to the remote-computer's WMI once and execute the three queries using the same connection?

$Array = @() ## Create Array to hold the Data
$Computers = Get-Content -Path .\hostnames.txt

foreach ($Computer in $Computers)
{

    $Result = "" | Select HostPS,Mfg,Model,Serial,OS

    $Result.HostPS = $Computer
    $ErrorActionPreference = "SilentlyContinue" ## Don't output errors for offline computers
    $OS = Get-WmiObject Win32_OperatingSystem -ComputerName $Computer

    $CS = Get-WmiObject Win32_ComputerSystem -ComputerName $Computer

    $BIOS = Get-WmiObject Win32_Bios -ComputerName $Computer
    $ErrorActionPreference = "Continue"

    $Result.Mfg = $CS.Manufacturer
    $Result.Model = $CS.Model
    $Result.Serial = $BIOS.SerialNumber
    $Result.OS = $OS.Caption

    $Array += $Result ## Add the data to the array
}

$Array | Export-Csv file.csv -NoTypeInformation

Answer 1

You can use CIM (which has a session option), more on CIM vs WMI ("WMI is the Microsoft implementation of CIM for the Windows platform")

$CIMSession = New-CimSession -ComputerName $RemoteComputer

Get-CimInstance win32_OperatingSystem -CimSession $CIMSession -Property Caption
Get-CimInstance Win32_ComputerSystem -CimSession $CIMSession -Property Manufacturer,Model
Get-CimInstance Win32_Bios -CimSession $CIMSession -Property SerialNumber

Answer 2

for me, the usual way to do that is to use Invoke-Command to run a script block on each target system. if you tell it to ignore errors, it will run in parallel [on the target systems] and return your data from the responders. to get the non-responders, compare the input list with the results. [grin]

here's a demo of the idea ...

#requires -RunAsAdministrator

# fake reading in a list of computer names
#    in real life, use Get-Content or (Get-ADComputer).Name
$ComputerList = @'
Localhost
BetterNotBeThere
127.0.0.1
10.0.0.1
::1
'@.Split("`n").Trim("`r")

$IC_ScriptBlock = {
    $CIM_ComputerSystem = Get-CimInstance -ClassName CIM_ComputerSystem
    $CIM_BIOSElement = Get-CimInstance -ClassName CIM_BIOSElement
    $CIM_OperatingSystem = Get-CimInstance -ClassName CIM_OperatingSystem
    $CIM_Processor = Get-CimInstance -ClassName CIM_Processor
    $CIM_LogicalDisk = Get-CimInstance -ClassName CIM_LogicalDisk |
        Where-Object {$_.Name -eq $CIM_OperatingSystem.SystemDrive}

    [PSCustomObject]@{
        LocalComputerName = $env:COMPUTERNAME
        Manufacturer = $CIM_ComputerSystem.Manufacturer
        Model = $CIM_ComputerSystem.Model
        SerialNumber = $CIM_BIOSElement.SerialNumber
        CPU = $CIM_Processor.Name
        RAM_GB = '{0:N2}' -f ($CIM_ComputerSystem.TotalPhysicalMemory / 1GB)
        SysDrive_Capacity_GB = '{0:N2}' -f ($CIM_LogicalDisk.Size / 1GB)
        SysDrive_FreeSpace_GB ='{0:N2}' -f ($CIM_LogicalDisk.FreeSpace / 1GB)
        SysDrive_FreeSpace_Pct = '{0:N0}' -f ($CIM_LogicalDisk.FreeSpace / $CIM_LogicalDisk.Size * 100)
        OperatingSystem_Name = $CIM_OperatingSystem.Caption
        OperatingSystem_Version = $CIM_OperatingSystem.Version
        OperatingSystem_BuildNumber = $CIM_OperatingSystem.BuildNumber
        OperatingSystem_ServicePack = $CIM_OperatingSystem.ServicePackMajorVersion
        CurrentUser = $CIM_ComputerSystem.UserName
        LastBootUpTime = $CIM_OperatingSystem.LastBootUpTime
        UpTime_Days = '{0:N2}' -f ([datetime]::Now - $CIM_OperatingSystem.LastBootUpTime).Days
        }

    }

$IC_Params = @{
    ComputerName = $ComputerList
    ScriptBlock = $IC_ScriptBlock
    ErrorAction = 'SilentlyContinue'
    }
$RespondingSystems = Invoke-Command @IC_Params
$NOT_RespondingSystems = $ComputerList.Where({
    # these two variants are needed to deal with an ipv6 localhost address
    "[$_]" -notin $RespondingSystems.PSComputerName -and
    $_ -notin $RespondingSystems.PSComputerName
    })

$RespondingSystems
$NOT_RespondingSystems

one item from the $RespondingSystems list ...

LocalComputerName           : [MySystemName]
Manufacturer                : System manufacturer
Model                       : System Product Name
SerialNumber                : System Serial Number
CPU                         : AMD Phenom(tm) II X4 945 Processor
RAM_GB                      : 8.00
SysDrive_Capacity_GB        : 931.41
SysDrive_FreeSpace_GB       : 735.15
SysDrive_FreeSpace_Pct      : 79
OperatingSystem_Name        : Microsoft Windows 7 Professional 
OperatingSystem_Version     : 6.1.7601
OperatingSystem_BuildNumber : 7601
OperatingSystem_ServicePack : 1
CurrentUser                 : [MySystemName]\[MyUserName]
LastBootUpTime              : 2018-10-19 7:01:51 PM
UpTime_Days                 : 7.00
PSComputerName              : [::1]
RunspaceId                  : e17c2741-ba8b-4fbb-b3db-9c7fd0d84f0d

the $NOT_RespondingSystems list ...

BetterNotBeThere
10.0.0.1