Microsoft is producing a steady stream of interim Windows 7 Service Pack 1 Builds on the way to the first beta development milestone, but so far has yet to make public any official details on the first major upgrade to the latest iteration of its Windows client. Information from a third-party source reveals that, between January 11 and March 2, Microsoft compiled no less than 35 builds of Windows 7 SP1, at the rate of almost one per day. According to Russian website Wzor, Windows 7 SP1 continues to be in pre-Beta stage, and will not graduate to fully fledged Beta for another month and a half.

Two builds of Windows 7 SP1 were reportedly already produced by the Redmond company in March, 7601.16517.100301-1718 and 7601.16518.100302-1530. Both belong to the winmain_sp branch. Wzor claims that it could leak any of the Windows 7 SP1 interim Builds that have been put together by Microsoft, but that it doesn’t see any point to this action until the service pack reaches the Beta development milestone.

As far as the 7601.16518.100302-1530 build string is concerned, 7601 represents the major build number, 16518 the minor version, and 100302-1530 the date and time at which the release was compiled, namely March 2, 2010 at 15:30.

At this point in time, work continues on Windows 7 SP1 with Microsoft keeping mum on all details related to the service pack. Wzor notes that the software giant is expected to make available Windows 7 SP1 Beta in mid-April 2010. Of course, the Redmond company has yet to either confirm or deny such a scenario. Below is a list with all the Windows 7 SP1 interim Builds since the first half of January 2010, courtesy of Wzor:

7601.16482.100111-1800;
7601.16483.100112-1500;
7601.16484.100113-1525;
7601.16485.100114-1500;
7601.16486.100115-1536;
7601.16488.100119-1500;
7601.16489.100120-1500;
7601.16490.100121-1509;
7601.16491.100124-1526;
7601.16492.100125-1657;
7601.16493.100126-1500;
7601.16494.100127-1500;
7601.16495.100128-1630;
7601.16496.100129-1554;
7601.16498.100202-1512;
7601.16499.100203-1500;
7601.16500.100204-1815;
7601.16501.100205-1500;
7601.16502.100208-1500;
7601.16503.100209-1500;
7601.16504.100210-1500;
7601.16505.100211-1536;
7601.16506.100212-1533;
7601.16507.100215-1600;
7601.16508.100216-1500;
7601.16509.100217-1500;
7601.16510.100218-1540;
7601.16511.100221-1400;
7601.16512.100222-1500;
7601.16513.100223-1552;
7601.16514.100224-1500;
7601.16515.100225-1623;
7601.16516.100226-1549;
7601.16517.100301-1718;
7601.16518.100302-1530.